Developments in the Renaissance: Sixteenth- and Seventeenth-Century Europe

3.2 Four Italian Naturalists: Cardano, Telesio, Patrizi, and Bruno

Girolamo Cardano (1501–1576) was the first of the Italian naturalists to put forth an unambiguous panpsychist philosophy. Spending most of his life in Milan and northern Italy, he was a renowned mathematician and physician, a prolific writer and inventor, and a diligent student of ancient philosophy. Stoicism affected both his metaphysical and his ethical beliefs. He studied Plato and Aristotle, ultimately siding with the Platonists in rejecting the Aristotelian picture of the universe.

Cardano’s conception of panpsychism is spelled out primarily in De natura (On Nature) and De subtilitate (On Subtlety), works in which he describes his theory of soul and its central role of maintaining the unity of all bodies. Soul is one of five universal qualities: “There are five principles of natural things: matter or ‘hyle,’ form, soul, place, and motion.” (1560/2013: 53) But soul clearly has a central role: “[Bodies] come into being from matter and form. But they are controlled by the soul, which in the more noble beings is mind … ; in bodies it is the principle of life.” (54) Here we see the Aristotelian influence both in the emphasis on form and in the distinction between mind and soul; all things have soul, but only the higher forms—such as humans—have mind. Cardano furthermore takes pains to emphasize the universality of soul: “Matter is everywhere, but cannot exist without a form, hence form too must be everywhere. But also a soul, whether because there is to be generation everywhere, or … because in every body there is evidently a principle of motion.” (27)

Cardano’s other Greek influences also reveal themselves in his writings. First there is his theory of the “active” (heat) and the “passive” (prime matter in De natura, and moisture in De subtilitate), which recalls the Stoic system. Stoic influence is also found in his reference to the pneuma, the “vital spirit” that circulates in the animal body and gives it life. Empedocles’ two forces of Love and Strife are reflected in Cardano’s “sympathy” and “antipathy.” According to Fierz (1983: xvii), “the main principle underlying [hidden] relationships is the sympathy and antipathy of all things, which partake in a common life.” Cardano does make a slight break with the Greeks in arguing against the designation of fire as an element. To him fire is heat, the active principle, which acts on the passive—matter and moisture—to produce form. This is a general ontological principle, and hence for Cardano “all permanent bodies, including stones, are always slightly moist and warm and of necessity animate” (66).

The animation of inorganic objects covers a striking list of properties, such that the usual distinctions are blurred. In De subtilitate Cardano writes extensively about compound or “mixed” substances—that is, things that are not pure elements. Such things are intrinsically alive:

The basis of growth and nutrition—and indeed of generation—is almost the same; there processes take place from the soul. In fact it is a task for the soul alone to be capable in this fashion of thinning out and then uniting and transmuting. If indeed there is anything devoid of life that could do this, it would above all be fire … yet it cannot. … And so all mixed things must be alive or have been so. (292)

Later he recaps this point: “We have shown previously that things that are mixed are alive; this is especially appropriate for stones. They are not simply alive, but also undergo diseases, old age, and later also death.” (366) Near the end of the work, he adds this:

Then it should be said, on comparable reasoning, that while a stone is in motion, it moves sideways by violence, and towards the center by nature, and thus on a middle line, because this would occur through recognition by the stone thus deliberating (deliberantis). (741)

Apparently a stone set in motion, subject to both impulsive and gravitational forces, is able to calculate, or deliberate on, the net force and to move in that direction.

Cardano seems not to have left much of an immediate philosophical legacy. His contributions are acknowledged today; however, Renaissance philosophers don’t appear to have been directly influenced by him, as we see little citation of his work. Such was not the case with Bernardino Telesio (1509–1588). Born eight years after Cardano, Telesio left a lasting imprint on Western philosophy, primarily through Bruno, Campanella, Bacon, and Hobbes. Hoeffding (1908: 92) called Telesio’s work “the greatest task undertaken by thought in the sixteenth century,” in large part because it forcefully struck out against the dominance of Aristotle and the Scholastics. Even more so than Cardano, Telesio relied on insights from nature to form his philosophy. Experience became a crucial aspect of inquiry and the cornerstone of all true knowledge.

Telesio’s philosophy is encapsulated in his magnum opus, the nine-volume De rerum natura (“On the Nature of Things”). The first edition, published in 1565 under a slightly different title, was revised in 1570 and then enlarged for a third and final release in 1586. In it Telesio overthrew the Aristotelian emphasis on matter and form, replacing it with an Empedoclean (and modern) conception of matter and force. Like Empedocles, Telesio saw two fundamental and opposing forces at work in the universe: Heat (an expanding and motive principle) and Cold (a contracting principle). These forces act on and shape the “third principle”: passive matter, which is associated with the earth. Thus, for Telesio all things consist of an active energy component, in the heat principle, and a mass component, in the passive matter of the earth: “All things [are] made of earth by the sun; and that in the constitution of all things, the earth and the sun enter respectively as mother and father.” (1586/1967: 309)

In addition to acting as material forces, Heat and Cold have the remarkable quality of perception. They necessarily tend to preserve themselves, particularly in the face of the other. Heat, insofar as it tends to stay hot, must somehow sense and know Cold, and repel it. And likewise with Cold. Ultimately we find a kind of balance or stalemate between the two principles, each existing in a state of dynamic tension (antiperistasis). Heat and Cold must possess the power to sense, to perceive, or else they simply could not exist. “It is quite evident that nature is propelled by self-interest.” (304) Self-preservation demands sensation (sensus). More than this, as an active principle of self-awareness, heat combines with matter to create a spiritual entity, a universitas spiritus that pervades the cosmos. This cosmic spirit is not only universally present, it is fully self-aware and thus aware of everything—a true spiritus omniscius omnino. It is a kind of world-soul, but one that derives from the inner nature of reality rather than as installed from without by some Demiurge.

In sum, all material objects embody the active principles of Heat and Cold. Therefore, all things must contain the power of perception. This is the basis for Telesio’s panpsychism. More properly, we refer to his position as pansensism—the view that everything is capable of sensation. As Giglioni says, “We can therefore say that Telesio understands sensus as the primordial sense of “being affected” pervading the entire universe. … [It] is an undivided and seamless process in which feeling, appetite, and motion mutate into each other.” Sensus is necessarily self-awareness, “and nature is accordingly conscious nature” (2010: 72–73).

Telesio effectively used the Non-Emergence argument to support his pansensist view. He claimed that it was inconceivable that mind should emerge from within matter unless it already had been there to some degree. Hoeffding (1908: 97) informs us that Telesio maintains “the impossibility of explaining the genesis of consciousness out of matter, unless we suppose matter to be originally endowed with consciousness.” Emergence is impossible, and therefore mind or soul is seen as inevitably present in the very structure of the cosmos—and in particular, in the fundamental active principles of Heat and Cold.

Telesio, like Cardano, was strongly influenced by Stoicism. Giglioni writes that “Stoic themes and their role in shaping his thought cannot be downplayed” (71). In addition to the active/passive distinction, his conception of the soul has many affinities to the Stoic pneuma. Like the pneuma, Telesio’s soul is corporeal, existing as a substance of “extreme tenuity and subtlety” (1586/1967: 305). Soul, like the pneuma, pervades all things, and both are embodiments of the active principle. That both Telesio and the Stoics should have reached a panpsychist conclusion, then, is not surprising.

But there is one important difference: Soul “possesses, besides sensation, the faculty of memory or retention” (Kristeller 1964: 100). This is significant because it is the first instance of memory playing a role in a metaphysical system—thus setting the stage for the later developments of Hobbes, Bergson, Russell, Bohm, and others. Unfortunately it is unclear how Telesio intends us to take his conception of memory: as merely a kind of persistent record of past experiences or, in a stronger sense, as an ability to recall past experiences. Regardless, it is an important milestone in panpsychist thinking.

Telesio’s heat and cold principles furthermore seem to find confirmation in modern physics. On some readings of cosmology, as the early universe began to cool after the Big Bang, a temperature differential emerged between radiation and matter. This thermal gradient supplies the universe with free energy that allows it to create order and structure in matter—everything from stars and planets to plants, animals, and people. In a sense, all material objects embody this thermal gradient, and owe their very existence to it. In the present context, we may note that the gradient occurs between the relatively hot radiation and relatively cool matter. Telesio’s “heat” and “cold,” understood as relative concepts, closely align with this modern conception. So conceived, heat and cold do in fact account for the existence of all order in the universe. And if we allow that our minds also emerged by this process of natural evolution, heat and cold also account for our sentience, self-awareness, and consciousness. Telesio seems to have been not far from the mark.²

Francesco Patrizi (1529–1597), like the other Italian naturalists, professed a deep dislike of Aristotelian philosophy and sought to place Platonism on at least an equal footing. In 1578, in recognition of his efforts, he was appointed to the world’s first chair of Platonic philosophy, at Ferrara. Patrizi, also a humanist and a poet, exchanged several philosophical letters with Telesio. His lyrical view of the world is reflected in his most important philosophical work, Nova de universis philosophia (New Philosophy of the Universe), in which he introduced the term ‘panpsychism’ (pampsychia) into the vocabulary of Western philosophy.

The Nova philosophia is a wide-ranging metaphysical treatise that lays out Patrizi’s theories of light, the soul, and the first principles of the cosmos. It is organized in four sections: Panaugia (“The All-Light”), Panarchia (“The All-Principles”), Pampsychia (“The All-Souls”), and Pancosmia (“The All-Cosmos”). The third section is of primary interest here, as it focuses on his interpretation of the world-soul and its particular manifestations in the natural world. In Patrizi’s cosmological hierarchy there are nine levels or grades of being; from highest to lowest: unity, essence, life, intelligence, soul, nature, quality, form, and body. Soul, notably, takes the middle and thus central role in the scheme, much as it did for Cardano. Furthermore, the nine levels of being are all fundamentally interconnected in what Brickman (1941: 34) describes as a deeply participatory process:

These nine grades are linked by a process of “partaking of one another”—participatio. This “partaking” Patrizi describes as an “inter-illumination,” through which beings are illuminated, come into existence, and are known. … Every grade partakes of each of those above it … and is also partaken of by each grade below it according to the capacity of the latter. Each grade … is [at once] a “partaker” (particeps), and is “partaken of” (participatus).

Patrizi echoes the language of participation as found in Neo-Platonism, especially in the work of Proclus and Pseudo-Dionysius. Such terminology builds on Plato’s original use of the concept as the means by which the phenomenal world interacts with the Forms.³

Soul, at the center of this participatory hierarchy, plays a major role in mediating between the upper spiritual grades and the lower earthly realms. At a minimum, it is clear that soul, in the form of the world-soul, penetrates all levels of being. The question, as before, is whether the individual objects of the world possess souls in themselves—i.e., true panpsychism—or whether they are merely extensions of the one world-soul. Patrizi clearly opted for the pluralistic view. He saw soul as a manifold entity, present both as distinct individuals and as united in the comprehensive world-soul. Kristeller (1964: 122) writes that “Patrizi does not treat the individual souls as [mere] parts of the world soul, but believes, rather, that their relation to their bodies is analogous to that of the world soul to the universe as a whole.” In the words of Brickman (1941: 41), soul is “both [unity and plurality], with the many contained in the one.”

Patrizi was the first to directly attack Aristotle’s logic regarding panpsychism, a position that would be reiterated later by both Bruno and Gilbert. All three men focused their criticism on Aristotle’s definition of psyche; and they all seem to have been unaware of his broader theory of the pneuma. As I noted, Aristotle believed the stars and heavenly bodies were animate, but he granted psyche to nothing in the earthly realm save plants and animals. Patrizi saw this as a logical inconsistency. On the one hand, the Peripatetics defined soul as the motive force behind a living, organic body. On the other, Aristotle himself stated that stars were ensouled even though they were not organic. One of the two positions must be wrong. Taking Aristotle’s implicit definition, Patrizi argues that an organic structure is not a prerequisite for having a soul, and so it is certainly possible that the cosmos as a whole, as well as the basic elements of matter that constitute it, also have souls.

Patrizi then runs through a series of brief arguments in support of his panpsychism: (1) How do we know that the elements do not have organs of some sort, and thus are “organic”? If they do, then this is a further argument on behalf of their souls (Design argument). (2) The cosmos is clearly the most perfect thing there is, and any perfect thing must have a soul or it would be less than perfect; therefore the world-soul exists (Design argument). (3) The elements give life and soul to all beings which have it, and nothing can be in the effect that is not in the cause; therefore, the elements must have souls (Non-Emergence). (4) All parts of the world experience birth, change, and destruction, yet they still have the power to hold together and persist; this cannot happen without soul (Indwelling Powers). These themes were developed by later philosophers, and Patrizi’s participatory ontology thus set the stage for the advances made by his immediate successors.⁴

Apart from Telesio, the other great philosopher of southern Italy was Giordano Bruno (1548–1600). Bruno’s philosophical system was rooted in his cosmology. The standard picture of the cosmos in the sixteenth century was essentially the same that Aristotle developed nearly 2,000 years earlier, and the same that Ptolemy had formalized in the second century AD: The universe was a finite space with the Earth at the center, and the stars and other heavenly bodies circulated around us on the celestial spheres. Throughout the centuries, a few thinkers had speculated otherwise, namely that the universe might actually be infinite. As early as 300 BC, Epicurus reasoned that the universe must be limitless: “The totality of things is unlimited … and having no limit, it must be infinite and without boundaries.” (Letter to Herodotus, 41–42) In the first century BC, Lucretius wrote:

The All that Is, wherever its paths may lead, is boundless. … There can be no end to anything without something beyond to mark that end. … Nor does it matter at which point one may stand: whatever position a man takes up, he finds the All still endless alike in all directions. (1977: 23; book I, 957–967)

Closer to Bruno’s time, the neo-Platonist philosopher Nicholas of Cusa (1401–1464) also discussed the possibility and significance of an infinite cosmos. Then came Copernicus’ De revolutionibus, published upon his death in 1543, which placed the sun at the center of the cosmos and the Earth in orbit around it. But Copernicus still maintained that the universe was finite, and that the celestial spheres circled around the solar system; in that sense he was less revolutionary than is commonly believed.

Bruno gathered these insights from Epicurus, Cusa, and Copernicus and pieced together a strikingly modern picture of the cosmos. His universe was an infinite space composed of infinitely many solar systems like our own. He was one of the first to use modern terminology, reserving ‘world’ for the Earth and other planets and using ‘universe’ to mean the whole infinite cosmos. Bruno saw neither the Earth nor the sun as the center of the universe; like Lucretius, he realized that, in an infinite cosmos, every place would appear as the center. Bruno said: “The Earth no more than any other world is at the center … . The Earth is not in the center of the universe; it is central only to our own surrounding space.”⁵

From this cosmology he drew important philosophical and metaphysical implications. First, he realized that there was an aspect of relativity to the cosmos. If the universe was, in a sense, the same throughout, then the same rules must apply everywhere. Hoeffding stated that, in Bruno’s cosmology,

every determination of place must be relative … . From the relativity of [place and] motion follows the relativity of time … . Nor have the concepts of heaviness and lightness any … absolute significance … . Nature is everywhere essentially the same [and] the same force is everywhere in operation. (1908: 124–126)

This “universality” of the universe meant that any physical or metaphysical conclusions arrived at here on Earth must of necessity apply throughout all existence.

Bruno’s panpsychism followed directly from his metaphysics. Nature has two internal constituent principles: form and matter. He takes this Aristotelian orthodoxy and interprets it in a Platonic or Plotinian manner. In particular, form is to be considered as produced by soul, i.e., the world-soul: “Bruno asserts that … every form is produced by a soul. For all things are animated by the world soul, and all matter is everywhere permeated by soul and spirit.” (Kristeller 1964: 133)

Bruno develops his panpsychism primarily in De la causa, principio, et uno (Cause, Principle, and Unity) and in De l’infinito universo et mondi (On the Infinite Universe and Worlds). Both were published in 1584, just after his visit to Oxford. Both were written in dialogue form, in the fashion of Plato.

It is in De la causa that Bruno states his view most clearly. In the second dialogue, the characters are elaborating on the animated nature of the cosmos. Adopting the language and concepts of his opponents, Bruno notes that, even within the old paradigm, the universe was ensouled: “There is no philosopher enjoying some reputation … who does not hold that the world and its spheres are animated in some way.” (1584a/1998: 42) Perhaps this is an exaggeration, yet he rightly acknowledges that panpsychism runs deep in Western philosophy. He then emphasizes the central aspect of ancient and medieval panpsychism: It is not only the world-soul that is animate, but all things individually are animate too. This view is reiterated in De magia (On Magic), in which the souls of individual things are at once distinct yet connected to the universal soul:

It is manifest … that every soul and spirit hath a certain continuity with the spirit of the universe. … The power of each soul is itself somehow present afar in the universe [and is] exceedingly connected and attached thereto. (in Singer 1950: 90–91)

In De la causa Bruno explicitly and concisely summarizes his view that “not only the form of the universe, but also all the forms of natural things are souls” (1584a/1998: 42). Thus he generalizes Aristotle’s idea—that soul is the form of living bodies—to all physical bodies.

Interestingly, Bruno then acknowledges the unconventionality of this view. The character Dicsono says “Common sense tells us that not everything is alive. … Who will agree with you?” Teofilo, speaking for the author, replies “But who could reasonably refute it?” In the manner of Patrizi’s criticism, Bruno offers a “proof” that focuses on the world-soul and the parts of the universe that are possessed by it. Again, Aristotle attributes soul to the stars and other heavenly bodies. Bruno, like Patrizi, considered it terribly inconsistent to hold that certain parts of the cosmos are privileged to have a soul and others are not. Thus, in keeping with his rule that the same laws apply throughout the universe, he logically concludes that all things, all “parts,” must be animated: “There is nothing that does not possess a soul and that has no vital principle.” (43)⁶

A skeptical Polinnio retorts “Then a dead body has a soul? So, my clogs, my slippers, my boots … are supposedly animated?” Teofilo (Bruno) clarifies his position by explaining that such “dead” things are not necessarily to be considered animate in themselves, but rather as containing elements that either are themselves animate or have the innate power of animation:

I say, then, that the table is not animated as a table, nor are the clothes as clothes … but that, as natural things and composites, they have within them matter and form [i.e. soul]. All things, no matter how small and minuscule, have in them part of that spiritual substance. … For in all things there is spirit, and there is not the least corpuscle that does not contain within itself some portion that may animate it. (44)

This distinction anticipates the views of both Leibniz and the twentieth-century process philosophers—Whitehead, Hartshorne, Griffin, et al.—who also deny mind to inanimate material objects but grant it to atoms, molecules, cells, and other so-called “true individuals.”⁷

Bruno’s line of thinking hints at the Indwelling Powers argument of Plato and the pre-Socratics. Matter either is animate outright or has the power of animation. We get a further indication of this standpoint when Bruno speaks of “the spirit, the soul, the life which penetrates all, is in all, and moves all matter.” As with the Greeks, soul has the power not only of animation but also of motion. This power is visible in the motion of the Earth, the stars, and other worlds, which have souls and are moved by them. In pressing his case that the Earth is ensouled, he even makes a passing reference to a version of the Continuity argument when he compares the structure of the Earth to that of a human being: “it is evident that waters exist within the earth’s viscera even as within us are humors and blood” (1584b/1950: 315).

Two other aspects of Bruno’s thought are relevant here. The first is his concept of the monad. He clearly was an atomist, and he believed that there existed some ultimately small and simple element of matter; he referred to these variously as atoms, minima, or monads. Unfortunately, he was not entirely clear or consistent in his definitions of these ultimates. Sometimes the monads are material entities (“the substance for the building of all bodies is the minimum body or the atom”—De minimo, in Singer 1950: 74). Other times they are something more ephemeral and mysterious; Singer describes them as “a philosophical rather than a material conception” and says that they “have in them some of the qualities of the whole” (72). Hoeffding (1908: 138) states that monads are “also active force, soul, and will.” The monad is not only an ultimate element of smallness; it is more generally a unity, and may equally apply to large-scale objects. Hoeffding elaborates: “[T]he sun with its whole planetary system is a minimum in relation to the universe. Indeed, even the whole universe is called a monad. … The world-soul too, even God himself, is called a monad.” (138–139) Bruno is sometimes credited with creating the concept of the monad, but the philosophical usage of the term goes back at least to Plato—‘monad’ derives from monas (“unity”). Plato’s younger contemporary Xenocrates made the monad a first principle of metaphysics, and identified it with a self-contemplating intellect or nous.⁸

The other important topic is Bruno’s theory of matter. He saw matter as a single substance that exhibited two modes: potenza (“power”) and soggetto (“subjectivity”). The power aspect of matter is revealed in its potential to act—that is, to exist or to be. Being is power, and power is the material aspect of matter—a clear connection to the concept of energy. Bruno’s other mode, subjectivity, can be seen as a manifestation of the soul in matter. Subjectivity determines the inherent nature of a thing, and distinguishes it uniquely from all other things. In short, potenza and soggetto represent the physical and mental modes of matter, respectively. Such a dual-aspect ontology is again a form of dualistic panpsychism, and it anticipates the later developments of Campanella, Spinoza, Schopenhauer, and others.

Bruno had a substantial influence on subsequent philosophers. Leibniz is a clear successor, particularly with his own conception of monads that so closely resembles Bruno’s.⁹ Spinoza, Goethe, Herder, and Schelling all were influenced by Bruno’s system.¹⁰ Even his implication of the will as an aspect of the monad anticipated the important advances of Campanella, Leibniz, Schopenhauer, Hartmann, and Nietzsche.

3.4 Campanella and the Seventeenth Century

Moving into thought that is more representative of the 1600s, we find an emerging scientific and objectivist worldview competing with the naturalistic and panpsychic theories of the Renaissance. The early rationalism and empiricism led the departure from Scholasticism and Church orthodoxy. This new rationalism of the sixteenth century was still open to panpsychist interpretations of the cosmos. But by the seventeenth century it began to harden into an objectivist and mechanistic worldview.

With respect to philosophy of mind, the 1600s were dominated by two of the most notable panpsychist philosophers in history, Spinoza and Leibniz. Additionally, I will examine the question of pansensism as discussed by Bacon and Hobbes. Also of note are the ideas of some lesser-known yet important figures, including Margaret Cavendish and Henry More. Even Locke and Newton made some interesting statements along panpsychist lines. The beginning of the seventeenth century was marked, though, by the culmination of Renaissance naturalism in the philosophy of Tommaso Campanella.

Campanella (1568–1639) was perhaps the last great Renaissance philosopher. His philosophy was marked by a strong opposition to Aristotle and an equally strong embrace of Telesio. His two major works—De sensu rerum et magia (On the Sense in Things and Magic), written in 1590 but not published until 1620, and Metafisica, published in 1638—both contained detailed and explicit arguments for panpsychism. Like the other Renaissance naturalists, Campanella emphasized an empirical approach to knowledge, but not in the restricted sense of the British empiricists. Rather, he combined experiential knowledge of nature with metaphysical first principles to form a complete philosophical system that was centered on his theory of the three “primalities” that were at the core of his panpsychism. That doctrine, one of the more original elements of his philosophy, pervades his entire system of thought. It claims that the essence of being consists of three fundamental principles: power, wisdom (or knowledge, or sense), and love (or will). Such characteristics had long been attributed to God—in the form of omnipotence, omniscience, and omni-benevolence. Campanella was the first to make them universally applicable. For him, they are aspects of all things, from God on down to the humblest bit of stone.

Power (potentia) has three connotations: the power to be (potentia essendi), the power to act (potentia activa), and the power to be acted upon (potentia passiva). The power to be is the first and the foremost of these, as it is the source of all existence. Without the potentia essendi a thing simply would not exist. Furthermore, existence demands the ongoing presence of this power in order to allow persistence through time. The powers to act and to be acted upon are related to Campanella’s theory of knowledge, and involve the ability to communicate the likeness of one thing to another, as will be discussed below.

The notion that power is the preeminent principle of existence is an advance from the Telesian conception of Heat and Cold, but it retains the essential reference to the idea of energy. And energy and power were virtually synonymous in the sixteenth century, long before power was defined as the rate of change of energy over time. Also, the potentia essendi anticipates certain very recent aspects of systems theory, particularly the idea of a “dissipative structure” as an entity that requires power, or energy expenditure, to maintain its existence.

The second primality, wisdom or knowledge, is explicitly mental. Campanella argues that, because all things sense, they can be said to know, and consequently to possess a kind of wisdom. First and foremost, things know themselves. Each thing knows of its own existence and its own persistence over time: “All things have the sensation of their own being and of their conservation. They exist, are conserved, operate, and act because they know.”¹³ Hoeffding (1908: 153) explains it this way: “Every individual being has an ‘original hidden thought’ of itself, which is one with its nature.” The same idea is explicit in the lengthy subtitle of Campanella’s De sensu rerum:

A remarkable tract of occult philosophy in which the world is shown to be a living and truly conscious image of God, and all its parts and particles thereof to be endowed with sense perception, some more clearly, some more obscurely, to the extent required for the preservation of themselves and of the whole in which they share sensation. (1620; in Bonansea 1969: 156)

This “remarkable” subtitle captures many aspects of his philosophy in a single sentence.

Campanella offered a number of arguments in support of his primality of wisdom and the attendant panpsychism. Several tend to take the form of definitional arguments or an appeal to first principles—for example, that knowledge is required for self-preservation, and hence all things must have active power—but he also employed the ancient Non-Emergence argument:

[I]f the animals are sentient … and sense does not come from nothing, the elements whereby they and everything else are brought into being must be said to be sentient, because what the result has the cause must have. Therefore the heavens are sentient, and so [too] the earth … . (1620; in Dooley 1995: 39)

Campanella did, however, introduce a new form of the Design argument for panpsychism, one that explicitly incorporates theology. He claims that, in the words of Bonansea,

all beings … carry within themselves the image or vestige of God and are essentially related to one another … . [God clearly possesses sensation and wisdom, and so] sensation is therefore to be extended to all beings. (1969: 157)

It is significant that Campanella saw all things as participating in God, and thus sharing his qualities. In fact, the theological argument applies to all three primalities: “Campanella holds that God … in effusing Himself into creatures, communicates to them power, knowledge [wisdom], and love, so that they may exist.” (145) It is interesting that Campanella, a devout Christian, looked to God as justification for his panpsychism. Perhaps he thought this would placate the Inquisition. Unfortunately for him, it did not. The Church was beginning to feel the pressure of the new naturalist philosophy, and so it struck back hard. At about the same time that Bruno was burned alive, Campanella, at the age of 32, was imprisoned by church authorities; he served 27 years for his beliefs. Fortunately he was able to continue writing, and even to smuggle out some complete manuscripts.

Campanella’s third primality, love, is a consequence of the primality of wisdom; things love existence, and such love follows naturally from self-knowledge. He explains it in Metafisica:

Beings exist not only because they have the power to be and know that they are, but also because they love [their own] being. Did they not love [it], they would not be so anxious to defend it … . All things would either be chaos or they would be entirely destroyed. Therefore love, not otherwise than power and wisdom, seems to be a principle of being … . (1638, in Bonansea, 162)

Thus it is clear that the three primalities are intimately linked. The primality of knowledge, for example, acts through the primality of power. The power to be acted upon represents the reception of an essence, the transfer of something from the object to the knower. The object is able to surrender this essence by its power to act. This essence is captured by the knower, is incorporated into its being, and is thereby changed. It is this change that constitutes knowledge. “Every sense,” says Campanella, “is a change in the sentient body” (1620, in Dooley 1995: 49). This change is not arbitrary. By incorporating an essence of the object, the knower becomes like the object. Assimilation occurs. Thus, knower and known merge, at least in part. To know something is to become like it.

Cassirer (1927/1963: 148) noted that such an epistemology entails a joint sharing of a common essence, and that furthermore a panpsychist theory of mind naturally follows:

[T]his unity [of knower and known] is only possible if the subject and object, the knower and known, are of the same nature; they must be members and parts of one and the same vital complex. Every sensory perception is an act of fusion and reunification. We perceive the object, we grasp it in its proper, genuine being only when we feel in it the same life, the same kind of movement and animation that is immediately given and present to us in the experiencing of our own Ego. From this, Panpsychism emerges as a simple corollary to [Campanella’s] theory of knowledge … .

Campanella has been revered throughout history as a man of powerful intellect and insight. In his own time he was acknowledged for his depth of thought. Battaglino called him “one of the rarest geniuses of Italy,” and Brancadoro exclaimed that “in him all fiery and most subtle powers are glowing and excel in the utmost degree.” Leibniz ranked him with Bacon, Hobbes, and Descartes.¹⁴ He remains, along with Bruno, an outstanding exemplar of Renaissance naturalism, and together they mark the turning point from a medieval, dogmatic, theological worldview to that of modern science and rationalism.¹⁵

3.5 The Early Scientific Philosophers

Campanella lived at precisely the time when scientific philosophy was first being formulated. Nearly the same age as Bacon (b. 1561) and Galileo (b. 1564), he created his naturalistic vision contemporaneously with their materialist and objectivist philosophy. Some intellectuals were able to accommodate both. Gilbert, as I have shown, integrated science and panpsychism. Johannes Kepler (1571–1630) saw soul as the force behind the movements of the celestial bodies, at least for the better part of his life. His first substantial work, Mysterium cosmographicum (1596), held to “the traditional conception of force as a soul animating the celestial bodies” (Jammer 1957: 82). The somewhat later De stella nova (1606) includes this comment:

Those motive powers of the stars share in some way in the capacity of thought, so that, as it were, they understand, imagine, and aim at their path—not of course by means of ratiocination like us human beings but by an innate impulse implanted in them from the beginning of Creation. (in Jung and Pauli 1952/1955: 173)

In 1609, Kepler published Astronomia nova, in which he discussed the “true doctrine of gravity” and noted that, wherever the Earth moved in space, heavy objects were always attracted to the Earth’s center “thanks to the faculty animating it” (85). He likened this animating force of gravity, which he called a species immateriata, to the animate force of magnets. In 1610 he claimed that gravity was identical to the magnetic force: “The planets are magnets and are driven around by the sun by magnetic force.” (89)

These themes continued in Kepler’s Harmonies of the World (1618). The epilogue (section 10) contains passages relating to the solar mind. He believed that the periodic and rational movements of the planets were “the object of some mind” (1618/1995: 240). He noted that “it is not easy for dwellers on the Earth to conjecture … what mind there is in the sun” (240–241). Yet, he asserted, mind in the sun followed as a necessary explanation of the “solar harmonies of movements”:

For as the sun rotating into itself moves all the planets by means of the form emitted from itself, so too … mind, by understanding itself and in itself all things, stirs up ratiocinations, and by dispersing and unrolling its simplicity into them, makes everything to be understood. (244)

The solar mind is the source of the harmonies: “there dwells in the sun simple intellect, pyr noeron, or nous, the source, whatsoever it may be, of every harmony.”

In 1621, at the age of 50, Kepler changed his mind. He decided that ‘force’ was a better term than ‘soul’. He concluded that gravitational attraction was something physical rather than supernatural:

Formerly I believed that the cause of the planetary motion is a soul. … But when I realized that these motive causes attenuate with the distance from the sun, I came to the conclusion that this force is something corporeal, if not so properly, at least in a certain sense. (90)

This is a remarkably frank and revealing admission. Because gravity decreases (regularly but non-linearly) with distance, it is a function of spatial dimension, and therefore it is of the physical world—hence, it cannot be soul. There is a deep implication here: Any entity that exhibits regularity in space or time must be physical in nature, and therefore cannot be mental or spiritual. In Kepler’s day, soul and mind were by definition mysterious and immaterial, lacking all tangibility and regularity. Any phenomenon that would admit to mathematization must necessarily be natural, physical, corporeal. This is in striking contrast to the view of the ancient Greeks. They saw regularity of motion as a clear indication of reason at work, and hence of soul in the cosmos. Kepler took the very same empirical phenomenon and came to the opposite conclusion: that mechanistic forces were the causal factors.

This, then, was the beginning of the mechanistic worldview—the mathematization of natural phenomena. Galileo took this up in earnest, and greatly advanced scientific philosophy. The natural philosophers, emboldened by their successes, soon sought mathematical descriptions everywhere. As a consequence, they began to push spiritual explanations to the sidelines. Materialist and mechanistic philosophy began to dominate Western thinking.

Two of the first materialist philosophers of the modern era were Francis Bacon (1561–1626) and Thomas Hobbes (1588–1679). Both lived during the transition from naturalistic panpsychism to scientific materialism. Both were born in the sixteenth century, but their writing and thinking were more allied to the seventeenth. Bacon was seven years younger than Campanella and was certainly aware of the panpsychist and pansensist philosophies that were circulating on the Continent, and of Gilbert’s De magnete.

Bacon could not abide the view that all things sense. For him, that ability was something that only livings things possessed. However, he was willing to admit that everything had some ability to perceive the local environment and to feel (though he did not use that word) temperature and force. Perception was, for him, a quality that all material objects possessed. Such a pan-perceptivist philosophy comes notably close to pansensism, and Bacon took care in spelling out his view in his Natural History (also called Silva Silvarum). In the early 1620s, near the end of his life, he wrote the following in introducing section IX of the aforementioned work:

It is certain that all bodies whatsoever, though they have no sense, yet they have perception; for when one body is applied to another, there is a kind of election to embrace that which is agreeable, and to exclude or expel that which is ingrate; and whether the body be alterant or altered, evermore a perception precedeth operation; for else all bodies would be alike one to another.

And sometimes this perception, in some kind of bodies, is far more subtle than the [human] sense; so that the sense is but a dull thing in comparison of it: we see a weatherglass will find the least difference of the weather in heat or cold, when men find it not. And this perception is sometimes at distance … as when the lodestone draweth iron. … It is therefore a subject of very noble inquiry, to inquire of the more subtle perceptions; for it is another key to open nature, as well as the [human] sense; and sometimes better. … It serveth to discover that which is hid.

Clearly, perception is a quality that is comparable to human sense, though “more subtle” and more mysterious. It clearly merits study, but Bacon seems not to know how to tackle the issue. He is not so bold as to predict that all phenomena will yield to materialist interpretations.

Hobbes, also aware of the pansensist philosophers, takes up their challenge in his 1655 work De corpore (On the Body).¹⁶ He first defines sense as “motion in some of the internal parts of the sentient; and the parts so moved are parts of the organs of sense.” This is a relatively accurate description of some sort of stimulus, such as light or sound, impinging on a sense organ and generating a nerve signal that moves through the body to the brain. He then confines sensation to living organisms: “The subject of sense is the sentient itself, namely, some living creature.” Then in section 5 he writes:

But though all sense, as I have said, be made by reaction, nevertheless it is not necessary that everything that reacteth should have sense. I know that there have been philosophers, and those learned men, who have maintained that all bodies are endued with sense. Nor do I see how they can be refuted, if the nature of sense be placed in reaction only. And, though by the reaction of bodies inanimate a phantasm [sensation] might be made, it would nevertheless cease, as soon as ever the object [causing the sensation] were removed. For unless those bodies had organs, as living creatures have, fit for the retaining of such motion as is made in them, their sense would be such, as that they should never remember the same … . For by ‘sense’, we [mean] … the comparing and distinguishing [of] phantasms. … Wherefore sense … hath necessarily some memory adhering to it.

Thus, like Bacon, Hobbes confronted the doctrine of pansensism that was associated with Telesio and Campanella.

Not uncoincidentally, it was also in De corpore that Hobbes first used the concept of conatus, meaning “striving” or “endeavor,” to refer to “all motion in general” (Herbert 1989: 64). If conatus is taken as an intentional quantity, then something mind-like inheres in all motion, and thus in all matter. But the degree to which Hobbes held that view is unclear.¹⁷

Hobbes recognized that the validity of pansensism hinges on the definition of “sense.” If sensing means only reaction, then he concedes that all things sense—this much is obvious. But he adds an additional condition: To sense requires memory, something only living organisms are presumably capable of. That qualification recalls Telesio’s claim that memory, along with sensation, is central to a proper conception of the soul.

However, the concept of memory may not be as transparent as Hobbes suggests. He seems to refer to a humanistic conception of memory, but there is no logical reason why the concept cannot be extended to general physical systems. A generalized conception of memory has at least two components: the ability to record experiences and the ability to replay or project them into the future. Humans record experiences through morphological changes in the brain, and then are able to replay them internally and to relate them externally via muscular action and language. Generalized memory requires, first of all, a permanent—or at least temporally persistent—change in the sensing body. That such a change occurs to all physical objects seems clear. Everything degrades and wears down to some extent, depending on the forces experienced. Ancient documents, fossils, rocks, and even planetary fragments can be dated with reasonable precision because of the permanent, cumulative record that all things acquire. This is a form of memory.

Furthermore, since physical objects do not communicate in the human sense, one may say that a form of memory exists if the record of experiences is present and available to an outside observer. Humans clearly can detect and measure physical changes over eons, and thus in this way the record of experience is replayed. Many changes are more subtle and may not be detectable with present technology. But this doesn’t alter the fact that all experiences are recorded and can theoretically be recovered.

Other thinkers have observed that inanimate objects can in fact display a kind of memory. William James, commenting on Fechner’s analysis of natural events, wrote:

[T]he event works back upon the background, as the wavelet works upon the waves, or as the leaf’s movements work upon the sap inside the branch. The whole sea and the whole tree are registers of what has happened, and are different for the wave’s and the leaf’s action having occurred. (1909: 171–172)

Henry David Thoreau’s book Wild Fruits contains a similar observation of the apple:

It will have some red stains, commemorating the mornings and evenings it has witnessed; some dark and rusty blotches, in memory of the clouds and foggy, mildewy days that have passed over it; and a spacious field of green reflecting the general face of Nature … . (2000: 87)

Bertrand Russell made comparable remarks in his Outline of Philosophy (1927b). After stating that memory is “the most essential characteristic of mind” (153), he cited an example of memory in “inorganic matter”:

A watercourse which at most times is dry gradually wears a channel down a gully at the times when it flows, and subsequent rains follow [the same] course. … You may say, if you like, that the river bed “remembers” previous occasions when it experienced cooling streams … . (155)

Logically, even other, more subtle perceptions—such as a gentle breeze, or the shadow of a hand on a leaf—also affect the system of a tree permanently, though such changes may be utterly undetectable. Henri Bergson further elaborated the philosophy of memory, defining it as the decisive factor in the graded transition from matter to mind; for an extended discussion, see his Matiere et Memoire (1896). Given a generalized conception of memory, then, it seems that a Hobbesian argument could support a pansensist or panpsychist view.

A final clue to Hobbes’ beliefs comes from the autobiographical essay The Prose Life (1677). Recalling an earlier episode in which he was challenged about the nature of sensation, he remarks: “From that time, [I] devoted [myself] to determining the nature of the senses, disputing whether corporeal body and all its parts were inert, or in a state of continuous movement, and (in consequence) totally sensate.”¹⁸ The passage is ambiguous but suggests that sensation is an intrinsic property of motion. But again, if the sensation is lost because of a lack of memory, it can have no functional value.

The last great philosophical figure born in the sixteenth century was René Descartes (b. 1596). His ontological dualism of mind and body, arising from his technique of methodical doubt, set the emerging scientific, mechanistic worldview on a track that it would follow for the next 400 years and beyond. The Cartesian system was rationalist to the core and pragmatic in intent. The non-human world was utterly aspiritual, without mind and without reason. Humanity was radically different from the other objects of the material universe, and stood alone in an isolated sphere, privileged in the eyes of God. Nothing close to panpsychism was conceivable in such a world.

Henry More (1614–1687) is perhaps the best-known of the “Cambridge Platonists,” a group that included Ralph Cudworth. A theist and an idealist, More came of age just as Cartesianism and the scientific philosophy began to implicitly threaten the philosophical standing of Christian theology. He was concerned that Descartes’ dualism implied a mechanistic universe that could operate without any intervention from God. At the same time, the pantheistic philosophy of Spinoza arose—a radical monism in which a non-Christian, non-personal God was immediately present everywhere. Neither of these options was acceptable to More.

More’s response was to suppose the existence of an intermediary force, the “Spirit of Nature,” that animated all matter on behalf of God.¹⁹ Matter in itself was inert, but the universal presence of the Spirit of Nature—which More described as “the vicarious Power of God upon Matter”—endowed all things with an internal animating principle. “The primordials of the world are not mechanical but spermatical or vital … , which some moderns call the Spirit of Nature.” Following Aristotle, this Spirit was seen to give form to all material things. It relieved God from the burden of continuous intervention and it saved the cosmos from an atheistic mechanism. It had numerous powers, including “self-penetration, self-motion, self-contraction and -dilation, and indivisibility,”²⁰ but the power of thought or reason was not among them.

Hence, More’s position qualifies as a quasi-panpsychism. It is interesting and relevant because it served as a direct spiritual response to the emerging materialist worldview and because More relied on theological arguments to support his view of spirit in matter, in a way comparable to Campanella. It also reflected the continuing influence of Plato and the concept of the world-soul.

Ultimately, More’s theory failed, largely because it attempted to defeat science on its own terms. As Greene says (1962: 461), “it becomes increasingly obvious that More’s attribution of function to the Spirit of Nature is highly arbitrary, and that it is a catch-all for the inexplicable.” Robert Boyle, famous for his attacks on the Cambridge school’s fuzzy metaphysical notions, complained that

[such agents] as the soul of the world, the universal spirit, the plastic power … tell us nothing that will satisfy the curiosity of an inquisitive person, who seeks to know … by what means, and after what manner, the phaenomenon is produced. (1674, in Bonifazi 1978: 68)

Finally, two of More’s contemporaries merit brief discussion. One of them is the physician Francis Glisson (1599–1677). Though most of his work was on medicine and human physiology, Glisson wrote a significant philosophical monograph, Treatise on the Energetic Nature of Substance, in 1672. Henry (1987: 16) calls it “one of the most original systems of philosophy” of the time and “one of the most profound attempts to develop a monistic solution to the mind-body problem.” And for present purposes, it makes the case for a strongly panpsychist ontology.

Glisson developed a theory of matter as composed of atom-like particles called minima naturalia. When coming together to form large-scale objects, these minima “communicate with each other” in a deliberate and conative manner; they “strive to adhere to each other due to a certain intrinsic property.” Employing explicitly panpsychist language, Glisson writes:

The particles, by perceiving the utility through which they enjoy their communion amongst themselves, love and desire this communion, and consequently they strive to maintain it—that is, they strive to adhere to each other in such a way that internal cohesion itself is nothing other than a movement or striving resulting from continuity, through which nature strives to conserve itself. Therefore, by means of natural perception and appetite, the cohesion is firstly based on continuity. (in Giglioni 2002: 250–252)

The various parts of objects thus seek to retain their connection and wholeness: “Here again we see nature perceiving the usefulness of its own parts, and loving them and striving (conatur) to defend them with all its strength.” As Giglioni sees it, this is a more modern and sophisticated form of panpsychism; for Glisson,

Substance is alive because it is capable of perceiving … . Therefore, if substance is essentially activity, activity is essentially perception, but natural perception … . Natural perception … founds the life of nature (vita naturae) without falling back again into the traditional aporias of animism and anthropocentrism. (2002: 254)

There is no divine Spirit of Nature at work here; matter is intrinsically perceptive and aware. God plays no role at all. It is a fundamentally naturalistic panpsychism.

The other person of note for purposes of the present discussion is Margaret Cavendish, Duchess of Newcastle (1623–1673). A poet and playwright, Cavendish also produced three major works on natural philosophy: Philosophical Letters, Observations upon Experimental Philosophy, and Grounds of Natural Philosophy. She advocated a form of materialism in which the cosmos was an organic whole composed of organic and animate parts. Her organicist materialism was offered in response to purely mechanistic materialism of the sort that Hobbes and Descartes had articulated.

Cavendish followed the thinking of the Stoics and the Renaissance naturalists in arguing that all of nature was alive and intelligent: “there is life and knowledge in all parts of nature, … and this life and knowledge is sense and reason” (Letter 30, 1664/1994: 26). She distinguished between two types of matter, the animate and the inanimate, which were mixed together in all material objects: “my opinion is, that all matter is partly animate, and partly inanimate, … and that there is no part of nature that hath not life and knowledge, for there is no part that has not a commixture of animate and inanimate matter” (25). Such properties were to be extended to the smallest portions of matter. As Perry recounts (1968: 185–186), Cavendish “felt that the world could not be made of atoms unless each one had life and knowledge.”

Animate matter was distinct from the inanimate in its capability for self-motion. It moved itself, and by physical connection it in turn moved the inanimate matter: “the animate moves of itself, and the inanimate moves by the help of the animate” (Letter 30: 26). Thus the motion of all physical objects was to be explained by reference to their animate portion. The intelligence in both forms of matter was realized as a kind of knowledge, initially in terms of self-knowledge and, ultimately, as a knowledge of God:

All parts of Nature, even the inanimate, have an innate and fixt self-knowledge, [and] it is probable that they may also have an interior self-knowledge of the existency of the Eternal and Omnipotent God, as the Author of Nature. (1655/1991: 8)

Cavendish’s metaphysical system was more poetic than analytic, but she established new standards for intellectual women of the seventeenth century. Her depiction of a compassionate and animate world provided inspiration to later feminist philosophers ²¹ and complemented the work of her male contemporaries.²²

3.6 Spinoza

Baruch Spinoza (1632–1677) sought a holistic interpretation of the cosmos. He created a unified ontology in which all phenomena, including the mental and the physical, are bound together in a single comprehensive picture. In this sense he reflected the inclinations of the Renaissance naturalists Cardano and Bruno. However, he lived in an era of new rationalism, led by Descartes—who was 36 years his senior—and in an era of emerging scientific materialist philosophy, led by Bacon, Galileo, and Hobbes. In addition, the religious theology of the day still held considerable influence and affected the thinking and writing of many intellectuals. Spinoza’s approach to unity took on aspects of all these influences; in Ethics (1677),²³ he built a logical, even mathematical case for the unity of God and nature, and of mind and matter—a case that incorporated the concept of the universal law.

Spinoza’s approach in Ethics was “geometrical” in the sense that it relied on a system of arguments patterned after mathematical formalism. Such a methodology was novel in philosophy, largely owing to the influence of Cartesian thinking.²⁴ But beyond pure methodology, Spinoza believed that mathematics could lead to true insight into the nature of reality. Mathematical formalism, he believed, reflected ontological formalism.

In his view, all of reality consists of a single substance, called “God” or “Nature” depending on the context and circumstances. Resurrecting the ancient pantheism of Plato and the Stoics, Spinoza saw God as the sum total of physical reality, the universe and everything in it constituting the substance of God. God was not a transcendent being, not a personal being, not a moral being, but simply the totality of existence.

This radical monism has to account for the apparent plurality of things in the world, and especially for the classes of things that we commonly call mental and physical. Spinoza proposes that the one substance, God/Nature, possesses infinitely many attributes. As limited beings, humans can perceive only the two primary attributes—those that he labels ‘extension’ (physical) and ‘thought’ (mental). Individual physical or mental entities, then, are considered modes or modifications of these attributes. A particular physical thing, such as an apple, is a “mode of extension,” and any specific mental event, such as a feeling of pain, is a “mode of thought.” The one substance God/Nature reveals itself to us through these two aspects. Hence Spinoza’s theory is appropriately described as a dual-aspect monism.

The two knowable attributes of extension and thought are distinct yet intimately related, as is to be expected in view of the underlying monism. They have, in fact, a very specific and fundamental connection: Every physical thing has a corresponding mental aspect, which Spinoza calls an “idea.” Conversely, every mental idea has a corresponding object, or thing. This is his unique brand of unity, known as psycho-physical parallelism: To every physical thing or event there corresponds an idea of that thing or event.²⁵

As the chain of physical events progresses in the world, there exists a parallel chain of mental events. These two chains of events track each other identically, one to one, and run forever in parallel. “The order and connection of ideas is the same as the order and connection of things.” (IIP7) Why? Because the thing and the corresponding idea are really the same thing—there is only one substance, after all:

[T]he thinking substance and the extended substance are one and the same substance, which is now comprehended under this attribute, now under that. So also a mode of extension [i.e. a particular thing] and the idea of that mode are one and the same thing, but expressed in two ways. (IIP7S)

It is incorrect to say that the chain of physical events causes the chain of ideas, or that the ideas cause changes in the physical events. There in fact is no causal connection between the two series at all. Causality is not even possible, because they are only two aspects of a single substance. There is no interaction, and hence no Cartesian interaction problem. This is a virtue of any monistic system.

Consider the special case of the human body. It is a particular physical thing, and thus a mode of extension. Corresponding to this mode, as to all modes, is an idea. The idea of the human body is not just some arbitrary mental entity; it is in fact the mind of that person: “The [physical] object of the idea constituting the human mind is the [human] body, or a certain mode of extension which actually exists, and nothing else.” (IIP13) Mind is the idea of body, and body is the object of mind.

Since the two aspects have no causal relationship, mind cannot affect body and body cannot affect mind. This is clearly stated in IIIP2: “The body cannot determine the mind to thinking, and the mind cannot determine the body to motion, to rest, or to anything else.” Yet for every body there is an associated mind. As the body changes, the mind changes in a corresponding way. They change together without causal interaction: “the mind and the body, are one and the same individual, which is conceived now under the attribute of thought, now under the attribute of extension” (IIP21S). So we see in Spinoza a metaphysical system in which we have a new way of comprehending the two realms of physical and mental. Each physical thing has an idea associated with it; conversely, every idea has a corresponding physical thing.

It is natural to think in terms of human beings, but Spinoza tells us that his method is “completely general.” His use of ‘body’, in fact, refers not just to a human body but to any physical object whatsoever. Hence the idea of any physical thing at all is in reality the mind of that thing. Every mode of extension has its corresponding mode of thought—or, in the simplest terms, every thing has a corresponding mind. Thus we arrive at Spinoza’s panpsychism. This is spelled out explicitly in the Scholium of proposition 13 in part II:

From these [propositions] we understand not only that the human mind is united to the body, but also what should be understood by the union of mind and body … . For the things we have shown so far are completely general and do not pertain more to man than to other individuals, all of which, though in different degrees, are nevertheless animate.

He then goes on to explain what he means by “different degrees”:

I say this in general, that in proportion as a body is more capable than others of doing many things at once, or being acted on in many ways at once, so its mind is more capable than others of perceiving many things at once.

Spinoza’s argument for panpsychism is often seen to rest solely on the Scholium of proposition 13, but this is not the case. There are at least three other claims for it. First, it is a logical consequence of propositions 3 and 11. Proposition 3 states that “in God there is necessarily an idea … of everything which necessarily follows from his essence,” i.e., all extant things. Hence all real things have ideas. Proposition 11 tells us that these ideas are minds. It does so not in general but by reference to the specific case of the human mind. Our mind is “nothing but the idea of a singular thing which actually exists,” i.e., some extant thing. (Proposition 13 informs us that this thing is nothing other than our body.) But it doesn’t matter what the particular singular thing is; what is relevant is that mind is the idea of some real thing. If minds are ideas, and all real things have ideas, then all real things have minds.

Further evidence can be found in proposition 1 of part III (“On the Affects”), where we find not so much an argument as a simple recognition that other things beside humans possess minds. Spinoza elaborates on the fact that humans have both “adequate” and “inadequate” ideas in their minds, and that either kind of idea is, however, adequate in God/Nature because “he also contains in himself, at the same time, the minds of other things.” Clearly the “other things” are non-human objects, and without reason to limit them, one must conclude that this covers all extant things.

Finally there is Spinoza’s doctrine of conatus, or striving. Part III observes that all things display a kind of effort or power toward maintaining existence—much along the line of Campanella’s potentia essendi. Like Campanella, Spinoza saw this striving as evidence of a vital or animate energy in things. The definitive passage is proposition 6: “Each thing, as far as it can by its own power, strives to persevere in its being.” Proposition 7 adds that this striving “is nothing but the actual essence of the thing.” And proposition 8 says that it is not merely occasional or sporadic but exists for “an indefinite time”; thus, striving is an eternal and essential aspect of any existing thing. In an earlier work—Descartes’ “Principles of Philosophy”—Spinoza defined life as “the force through which things persevere in their being.” Assuming that he maintained such a view through the Ethics, one can read the conatus doctrine as a form of hylozoism. This again would be consistent with a generally panpsychic outlook.

One further passage from Spinoza is worth mentioning here, though its status as a basis for panpsychism is unclear. In his 1674 letter to G. H. Schuller (letter 58), he elaborates on his theory of free will and determinism. By way of example, he cites the case of a stone that is “set in motion” through the air, as when thrown by someone. A stone set in motion is not unlike, say, a human set in motion; each moves through the world, reacting to various impulses and forces. Spinoza writes:

Next, conceive now, if you will that while the stone continues to move, it thinks, and knows that as far as it can, it strives to continue to move. Of course since the stone is conscious only of its striving, and not at all indifferent, it will believe itself to be free, and to persevere in motion for no other cause than because it wills to. And this is that famous human freedom which everyone brags of having … . (1674/1994: 267–268)

It is not clear whether he means to say that the stone does think and is conscious or whether this is merely a hypothetical example. His point here, of course, is to refute the notion of free will, not to examine the mind of a stone. But it is a suggestive passage nonetheless.²⁶

In view of the controversial status of panpsychism, it is perhaps unsurprising that many scholars have denied that Spinoza’s view is panpsychist. This is particularly true of commentaries published in the early and the middle years of the twentieth century. Of the early commentators, Joachim (1901) is the most neutral. But we find clearly hostile readings in Wolfson 1937 (ideas are really just “forms,” not minds), in Fuller 1945 (“ideas can scarcely be regarded as individual psychical entities, like souls or minds”), in Hampshire 1951 (“only humans have minds”), in Parkinson 1953 (that all things are animate is merely an inconsequential “curiosity”), and in Curley 1969 (ideas are just “true propositions”). Interestingly, though, later commentaries display a clear trend toward greater sympathy for the panpsychist interpretation. Pro-panpsychism readings are found in Harris 1973, in Bennett 1984, in Delahunty 1985, in Allison 1987, and in Curley 1988. Even Hampshire (2002) seems to have turned toward a more sympathetic interpretation.²⁷ Curley (1988: 64) seems to go so far as to argue for a kind of super-panpsychism in Spinoza, in which not only do extended, physical things have minds, but so too do modes of all the other unknowable attributes. Few Spinoza scholars seem to acknowledge this large-scale shift toward a panpsychist interpretation.

3.8 Leibniz

The panpsychism of Gottfried Leibniz (1646–1716) was rooted in his conception of the monad. Yet even before his development of that concept he found reason to see all things as animate. Some of Leibniz’s earliest philosophical writings date from the mid 1680s, when he was about 40 years old. In Primary Truths he asserted, with emphasis, that “every particle of the universe contains a world of an infinity of creatures” (1686a/1989: 34). The same year, in a letter to Arnauld, he defined soul as “substantial form” and attributed it to all things with a “thoroughly indivisible” unity: “I assign substantial forms to all corporeal substances that are more than mechanically united.” (1686b/1989: 80) The extent of such objects is presumed to be widespread but is left unspecified.

Leibniz seems to have had at least two reasons for thinking this way. The first was Leeuwenhoek’s recent (ca. 1660) invention of the microscope and his discovery of “animalcules” in apparently clear drops of water. This was dramatic empirical evidence that hitherto unseen forms of life resided in unsuspected places. A plethora of life implied a plethora of souls. Leibniz admitted as much in a 1687 letter to Arnauld: “[E]xperience favors this multitude of animated things. We find that there is a prodigious quantity of animals in a drop of water.” (1989: 88) Second, Leibniz found theological reasons for this belief. An ensouled universe was more nearly perfect than one in which only mankind possessed soul, and thus was more in line with the perfection of God. It is, he wrote, “in conformity with the greatness and beauty of the works of God for him to produce as many [true] substances as there can be in this universe” (1687/1989: 87). It is “a perfection of nature to have many [souls].”

Leibniz did not make detailed reference to the notion of the monad until 1698, and did not develop the monad theory fully before Principles of Nature and Grace (1714a) and Monadology (1714b). However, even his writings leading up to the concept of the monad indicate that he associated the soul or substantial form with an atomic or point-like entity. As early as 1671, at age 25, he wrote that “the soul, strictly speaking, is only at a point in space” (in Hoeffding 1908: 335). In 1695 he wrote of “true unities” underlying reality:

[I]n order to find these real unities, I was forced to have recourse to a real and animated point, so to speak, or to an atom of substance which must include something of form or activity to make a complete being. (1695: 139)

Here again we see the association of animation with a point-like entity. Leibniz continues:

I found that [the atoms’] nature consists in force, and that from this there follows something analogous to sensation [i.e. perception] and appetite, so that we must conceive of them on the model of the notion we have of souls.

Like Bruno’s, Leibniz’s monad was a point-like, atom-like entity that constituted all extant things. The monad was the true substance of the world, and all other things were simply collections or aggregates of these monadic substances: “These monads are the true atoms of nature, and, in brief, the elements of things.” (1714b, section 3) Monads, he writes, have the rather paradoxical quality of being at once absolutely simple and “without parts” and yet being absolutely unique. In fact every monad is a kind of focal point for its own perspective on the universe, and is internally as complex and ordered as the entire cosmos:

[T]here must be a plurality of properties and relations in the simple substance [i.e. monad], even though it has no parts. (1714b, section 13)

[E]ach monad is a living mirror … which represents the universe from its own point of view, and is as ordered as the universe itself. (1714a, section 3)

And these simple yet complex monads have other relevant characteristics. First, they are “windowless”—they have no direct interaction with the outside world or with each other, and they are exempt from physical causality. Second, and more to the point, monads have two primary capabilities: perception and appetite. Perceptions are the states that monads pass through as they continually reflect their ever-changing perspective on the universe. The appetite, or desire, “brings about the change or passage from one perception to another” (section 15). The importance of these two qualities cannot be overestimated. All mind, Leibniz says, even the simplest, possesses at least the subjective property of perception—feeling—and the intentional property of will or appetite. This aligns well with much of present-day philosophy of mind, which holds that the mind seems to have two irreducible components, namely the qualitative and the intentional.

Monads thus serve as the theoretical basis for Leibniz’s panpsychism. Consider this passage:

I believe that … it is consistent neither with the order nor with the beauty or the reason of things that there should be something vital or immanently active only in a small part of matter, when it would imply greater perfection if it were in all. And even if … intelligent souls … cannot be everywhere, this is no objection to the view that there should everywhere be souls, or at least things analogous to souls. (1698/1956: 820; section 12)

In Monadology (section 66) he reiterates this view: “we see that there is a world of creatures, of living beings, of animals, of entelechies, of souls in the least part of matter.” Clearly panpsychism was a consistent and essential aspect of Leibniz’s metaphysics.

Leibniz faced three perplexing and related questions: How can point-like entities combine to form apparently solid objects? How can a theory of monads account for the high-level soul or mind that is found in humans? Why do certain collections of monads (e.g., humans) possess high-level unified minds whereas others (e.g., rocks) do not?

The answers to these questions center on two concepts: that of the aggregate and that of the dominant monad. Throughout his philosophical career, Leibniz emphasized the distinction between mere collections or aggregates of monads and collections with a real and substantial sense of wholeness and unity. Aggregates include objects or systems that are loosely organized, such as a “heap of stones,” an “army,” a “herd,” or a “flock.” They furthermore include objects that are apparently solid and whole—rocks, tables, houses, shoes, and so on. In his theory of aggregates, Leibniz followed Democritus in asserting that aggregates only appear to be whole and unified.³⁰ Their unity is only in our minds, not in reality. This is clear in the cases of flocks and herds, less so in the case of a solid rock. Yet Leibniz saw them as on a continuum and as distinct from other objects—humans, other animals, plants, monads—that were truly integrated beings. Integrated objects possess a “substantial unity” that demands “a thoroughly indivisible and naturally indestructible being” (1686b/1989: 79). But this issue is metaphysically controversial.

The substantial unity of true individuals is realized physically by the dominant monad. Of the countless monads making up a person’s body, one monad somehow comes to dominate the others and to draw them together into cohesiveness.³¹ This dominant monad, or “primary entelechy,” is the soul of the person. The human body, in itself, is considered a mere aggregate; but together with the dominant monad or soul it constitutes a “living being”:

[The dominant monad] makes up the center of a composite substance (an animal, for example) and is the principle of its unity, is surrounded by a mass composed of an infinity of other monads, which constitute the body belonging to this central monad. (1714a, section 3)

This again is the case for humans, animals, plants, and the microscopic animalcules in the droplets of water. Such things are in fact doubly ensouled: They consist of animate sub-monads and they possess a single unifying soul in the dominant monad. Aggregates, by contrast, are not animate in themselves, but of course are still composed of the soul-like monads. Therefore even aggregates are animate in a restricted sense. This is more or less identical to Bruno’s view, but Bruno offered no theory as to why it should be the case. Leibniz at least proposed the outline of a theory, even though he left many questions unanswered—including how and why one monad comes to dominate and why this happens only in certain collections of monads.

These open questions point to an incompleteness in Leibniz’s theory. He was never clear, for example, on whether large-scale objects or systems, such as the Earth, were to be considered “substantial unities.” Only once, in an early letter to Arnauld, did he address this directly:

[I]f I am asked in particular what I say about the sun, the earthly globe, the moon, trees, and other similar bodies. … I cannot be absolutely certain whether they are animated, or even whether they are substances. (1686b/1989: 80)

Leibniz later accepted plants as animated beings, but the general status of large-scale systems remained open for him throughout his life.

Two other points indicate Leibniz’s uncertainty about the status of aggregates. First, his final two major philosophical essays—Principles of Nature and Grace and Monadology—rarely mention the subject. Principles doesn’t discuss it, focusing instead on living beings and their dominant soul monad. Monadology actually reverses Leibniz’s usual terminology; he divides reality into “simple substances” (monads) and “composite substances,” wherein the composite “is nothing more than a collection, or aggregate, of simples” (section 2). Apparently, then, all living beings are to be considered aggregates. But the remainder of Monadology contains no further discussion of the soulless aggregates. That these two essays constitute a summary of Leibniz’s metaphysical system is all the more significant.

Second, there is Leibniz’s late (ca. 1712) introduction of the vinculum substantiale (substantial chain) as a kind of glue that bonds together the monads of a living being. He consistently affirmed that ordinary material objects, such as rocks, are mere phenomena and only appear to be unified beings. But this also holds for the body of an animal, which, apart from its dominant soul or mind monad, is also a mere aggregate. Concerned to differentiate the two, and knowing that “points can never form a continuum,” he introduced a substantial chain to link together all monads of true living beings. This chain is both “real” and “substantial,” and it is to be “added to the monads in order to make the phenomena real” (1716/1989: 203). In retrospect the whole concept of the vinculum substantiale seems an ad hoc construction to account for the differing properties of aggregates. It is in fact a whole new ontological category, distinct from the monads themselves. We are given no explanation of how this chain comes to exist, or of why it is present only in select aggregates and not in others.³²

A final point of note concerns the influence on Leibniz of the earlier panpsychists. Bruno clearly impressed him, and Leibniz’s use of the monad concept may well have been inspired, if only indirectly, by Bruno’s work. Consider the passage in section 66 of Monadology cited above: “we see that there is a world of creatures, of living beings, of animals, of entelechies, of souls in the least part of matter.” This seems to recall an earlier passage in which Bruno asserted that “there is not the least corpuscle that does not contain within itself some portion that may animate it.” And there were surely other Renaissance influences. We know for certain that Leibniz had read Campanella and thus was aware of Italian naturalism. He even seems to have picked up a central element of Campanella’s ontology: Monadology contains a virtual word-for-word reiteration of Campanella’s doctrine of the three primalities of power, wisdom, and love or will:

God has power, which is the source of everything, knowledge, which contains the diversity of ideas, and finally will, which brings about changes … in accordance with the principle of the best. (section 48)

Just before he introduced the term ‘monad’ in the late 1690s, Leibniz corresponded with the philosopher Francis van Helmont and was “considerably influenced” by him.³³ Helmont was a close associate of the British philosopher Anne Conway, who in turn was a colleague of Henry More. More cited the term ‘monad’ in his Cabbalistic axioms.³⁴ It is entirely plausible that either Conway or More (or both) picked up Bruno’s concept of the monad and incorporated it into their own writing. Thus, it may have been by way of More, Conway, and Helmont that Bruno’s influence was felt. In the end, Leibniz seems to have adopted many ideas of the Italian naturalists, elaborating and articulating them in his own terminology.

3 Developments in the Renaissance: Sixteenth- and Seventeenth-Century Europe

3.1 Transition to the Renaissance