Whitehead's system may be interpreted as a majestic attempt at recasting Leibniz's theory of monads in terms of sounder ontological categories. After a brief introductory section on the sources of Whitehead's knowledge of Leibniz's philosophy, the paper explains why Whitehead turned to Leibniz for metaphysical inspiration. Attention then shifts to Whitehead's understanding of the problems involved with Leibniz's theory of monads and his alternative explanation of monadic causation. Whitehead's endeavour to install windows in Leibniz's monads may not be entirely convincing, but there are philosophical gems scattered here and there in his analyses – true moments of insight that repay close examination.
Like many of his contemporaries, Whitehead believed that Leibniz had provided a correct account of the ultimate principles of reality with his theory of monads.2 But in the theory of pre-established harmony he saw the greatest stumbling block to its acceptance. In his metaphysical trilogy – Science and the Modern World (1925), Process and Reality (1929), and Adventures of Ideas (1933)3 – he constructed a bewildering complex theory of reality and our place in it. In these books, he also offered an analysis of the strengths and weaknesses of Leibniz's theory of monads, together with a positive account of monadic interaction.
Whitehead was a man of impressive talents and erudition. He also had the good luck of working in Cambridge in close personal contact with exceptional colleagues and at a time when both science and philosophy were there flourishing.4 But he was not trained either as a philosopher or a historian of philosophy. We know little or nothing about his private studies and ruminations. The appreciative tenor of many of his passages5 suggests that he must have read some of Leibniz's writings quite carefully. To the best of my knowledge, however, all of his allusions to Leibniz in his printed works are to the Monadology.6
As far as scholarly knowledge of Leibniz's philosophy is concerned, Whitehead apparently owes it to two books. One is Louis Couturat's La Logique de Leibniz (1903), the other Bertrand Russell's A Critical Exposition of the Philosophy of Leibniz (1900). Both thinkers emphasize the significance of Leibniz's logic for a general understanding of his philosophy. Leibniz's theory of monads, Russell says, looks like a fairy tale unless one realizes that it follows from a few basic assumptions – the most important of which is the logical theory that all propositions are subject–predicate in form. As we shall see, Russell's interpretation profoundly shaped Whitehead's understanding of Leibniz's metaphysics.7
Whitehead explains what he takes to be the contemporary relevance of Leibniz's metaphysics in Science and the Modern World. One of the factors that enabled the great scientists of the seventeenth and the eighteenth centuries to make their momentous discoveries, he contends, was their stubborn refusal to deal with basic speculative questions. In their physical investigations, they registered empirical regularities and accepted them as mere matters of fact. This procedure was justified pragmatically by the success of science in predicting the course of nature. But for a fully rational mind – one which takes seriously Leibniz's Principle of Sufficient Reason – this method cannot be satisfactory. Reason at its best craves understanding; it cannot acquiesce in the factum brutum of a mere acknowledged regularity.
In Science and the Modern World, Whitehead meditates upon the historical fate of this strong conception of rationality as the search for ultimate explanations. In this context, he discerns a deep meaning in the violent death of the Renaissance thinker Giordano Bruno. This occurred just before the rise of modern science:
Giordano Bruno was the martyr: though the cause for which he suffered was not that of science, but that of free speculative imagination. His death in 1600 ushered in the first century of modern science in the strict sense of the term. In his execution there was an unconscious symbolism: for the subsequent tone of scientific thought has contained distrust of his type of general speculativeness.
(SMW 1)
The eclipse of speculative reason in early modern thought is best exemplified in the way the question of the ultimate nature of things was approached. Modern science adopted as its ontological framework a materialistic atomism uncritically derived from antiquity. For the limited purposes of ordering and predicting phenomena, this ontology worked perfectly. But fundamental questions remained unanswered.
On a materialistic basis, for example, it is impossible to understand why there should be living, experiencing organisms. There is nothing in the idea of inert bits of matter that enables us to see why they should give rise to life and experience. The mutual relationships of material particles may be conceived as becoming increasingly complicated in the course of evolution. The problem of understanding the transition from the purely material aggregate to the living sentient organism still remains. ‘A thoroughgoing evolutionary philosophy’, Whitehead writes, ‘is inconsistent with materialism. The aboriginal stuff, or material, from which a materialistic philosophy starts is incapable of evolution’ (SMW 107). For Whitehead, you cannot be a materialist and believe yourselves to be rational – not if the word ‘rational’ is understood in its deep, speculative sense.
Whitehead's anti-materialist reasoning bears a strong similarity to Leibniz's Mill-Argument in the Monadology, an argument that will have hardly failed to attract Whitehead's attention although he does not discuss it explicitly. Contemplate the material machine as much as you will, enlarge it and step into it in your imagination. Still, you will not find anything there that explains why the material machine should also be thinking. In a letter to Lady Masham, commenting upon Locke's suggestion that God may endow matter with a power to think, Leibniz makes the point even more forcefully:
It is true that the illustrious Locke maintained in his excellent Essay … that God can give matter the power of thinking, because he can make everything we can conceive happen. But then matter would think only by a perpetual miracle, since there is nothing in matter in itself, that is, in extension and impenetrability, from which thought could be deduced, or upon which it could be based.
(AG 290; my emphasis)
God could give matter the power of thinking; matter could never generate thought. Why? If there is nothing to matter but extension and impenetrability, the origination of mind out of matter would be a brute fact. If matter and mind happen to be thus conjoined, this connection would have to be established by an external agency (God) as well as explicable by reference to it:
God, in the case of thinking matter, must not only give matter the capacity to think, but he must also maintain it continually by the same miracle, since this capacity has no root, unless God gives matter a new nature.
(AG 290; my emphasis)
Leibniz and Whitehead are addressing what is nowadays called the ‘hard’ problem of consciousness. Their argument is a very powerful one. If consistently carried through it leads to the conclusion that, in one way or another, mind must be a fundamental feature of reality. As Whitehead has it, the principles of things cannot be ‘vacuous actualities’ (PR xiii), entities entirely devoid of mentality.
This is, in brief, how the Leibniz–Whitehead critique of materialism works:
There must be an explanation of everything that is – of its very existence as well of its specific way of being.
Mental events (such things as thoughts, memories, sensations, emotions) undoubtedly exist.
There is obviously nothing in the concept of a material (merely extended) atom or in that of their combination into larger material aggregates that explains why mental events shall exist.
Hence, materialism – the view that only material atoms truly are and anything else must be explained by reference to them – cannot be the last word about the nature of things.
Of course, such an argument is not immune from attacks. It seems natural to ask (1) why the Principle of Sufficient Reason should be accepted in the first place (which would lead to a complicated discussion of what has to be regarded as an ‘explanation’). Eliminative materialists may want to reject (2), while believers in radical emergence would deny (3). But the reasoning surely has a strong prima facie plausibility and is as good as any to be found in philosophy.
Whitehead knew very well that mere philosophical reasoning would never make a successfully developing science deviate from its course. But he lived in a time of scientific revolution. Like many of his contemporaries – and because of his solid scientific education, probably much better than most – Whitehead realized that recent developments in biology (the theory of evolution) and physics (quantum physics, relativity theory) had destroyed any basis for believing in a theory of reality as simple as seventeenth-century materialism. This theory, he argued, is ‘entirely unsuited to the scientific situation at which we have now arrived’ (SMW 17). Philosophers, he concluded not without polemical undertones, have neither to indulge in historical studies nor provide detailed but sterile analyses of isolated technical problems; rather, they have to engage in the construction of a new metaphysical scheme (cf. PR xiv).
The one book in which Whitehead makes the utmost effort to be both complete and precise in the elaboration of his new ontology is Process and Reality. ‘On the whole’, Whitehead says here, ‘this is the moral to be drawn from the Monadology of Leibniz. His monads are best conceived as generalizations of contemporary notions of mentality’ (PR 19). It seems natural to read in this passage an allusion to an argument Leibniz develops in the three opening paragraphs of the Monadology.
The Monad, which we shall discuss here, is nothing but a simple substance that enters into composite – simple, that is, without parts. And there must be simple substances, since there are composites; for the composite is nothing more than a collection, or aggregate, of parts. But where there are no parts, neither extension, nor shape, nor divisibility is possible. These monads are the true atoms of nature and, in brief, the elements of things.
(§§1–3, AG 213)
Leibniz tells us here that the basic principles of reality (monads) cannot possibly be extended. Extended things are infinitely divisible, whereas the ultimate constituents of reality (substances) cannot have parts. The material (extended) atoms of modern science are useful abstractions, yet they cannot be regarded as metaphysically ultimate.
As Leibniz writes in a Letter to De Volder, ‘the atoms of the Democriteans … cannot, as commonly understood, be found in nature, nor are they anything but incomplete thoughts of philosophers who have not inquired sufficiently well into the nature of things’ (AG 175; my emphasis). Whitehead agrees with this evaluation. On his understanding, science takes an abstract view of the nature of things. Scientific theories provide us with a description of the structural aspects of reality, but say nothing about the intrinsic nature of the things that support that structure. ‘Science ignores what anything is in itself. Its entities are merely considered in respect to their extrinsic reality, that is to say, in respects to their aspects in other things’ (SMW 153). To conceive of scientific concepts as adequate characterizations of things is to mistake the abstract (i.e., the ‘incomplete’) for the concrete – a mistake Whitehead refers to as ‘the fallacy of misplaced concreteness’.
The argument against materialism based upon the Principle of Sufficient Reason that has been considered in the previous section is ambiguous as to its positive metaphysical implications. The view that purely material particles cannot account for the existence of mind shows that the concept of matter as sheer extension requires revision. By itself, however, the argument provides no clue as to the kind of correction that is needed. That line of reasoning is consistent both with the view (1) that the basic principles of reality have a mental as well as a physical side, and (2) the more radical view that such principles are purely mental.8 The argument at the beginning of the Monadology would seem to have clearer metaphysical implications. In order to reach the basic principles of reality, we are now apparently told, we have to bypass the realm of the material altogether.
In this way, Leibniz may be read as committing himself to a form of panpsychistic idealism or, as it is perhaps better called, mentalism – the doctrine that monads are mind-like entities. On this view, our own mind becomes the paradigm of substantiality.
If we wish to call soul everything that has perceptions and appetites … then all simple substances or created monads can be called souls.
(§19, AG 215)
Leibniz's descriptions of the monads are brief but suggestive. Each monad is a unique synthesis of perceptions (§78; AG 223). Moreover, their inner life is on-going activity (§11; AG 214), as each monad is driven by an inner desire (appetition) for novel experiences (§15; AG 215).9 Whitehead applauds at this understanding of the monad as an experiential process-unit. ‘Each monadic creature is a mode of process of “feeling” the world, of housing the world in one unity of complex feeling, in every way determinate’ (PR 80). But of his own metaphysics, he also says:
This is a theory of monads; but it differs from Leibniz's in that his monads change. In the organic theory, they merely become.
(PR 80)
For the time being, it is important to notice the point of distinguishing sharply between the concept of change and the concept of becoming. This highlights what Whitehead takes to be a fundamental tension in Leibniz's metaphysics. On the one hand, Leibniz's monads are mind-like currents of experience. On the other, Whitehead thinks, they are conceived by Leibniz in an Aristotelian fashion as substrata to which qualities inhere. On this view monads ‘change’ – that is, each monad is a permanent substratum that loses old properties and acquires new ones.
Whitehead is unsatisfied with this Aristotelian account of the monads’ ontological structure for several reasons. How is it possible to conceive of energetic monads in terms of the static notion of an underlying bearer? The notion of substance as a substratum clashes with Leibniz's other fundamental idea that a substance is essentially a being capable of action. And how could categories such as those of ‘thing’ and ‘properties’ be of any use in describing immaterial beings? These categories had been developed by primitive men in primitive times to deal with ordinary material objects such as rocks, trees and mountains. These concepts are of great practical utility, but they were not meant to have any deep ontological significance.
But the main obstacle that prevents understanding monads as substrata, Whitehead argues, is their experiential nature. The concept of the monad as embodying a point of view is a thoroughly relational concept. We experience the world by grasping and incorporating aspects of it into the unity of a new perspective. This process must involve for Whitehead some sort of actual relationship between the experiencing subject and the experienced object. But there is no place for relations within a metaphysical scheme that acknowledges only the reality of properties and their underlying bearers.
Within such a scheme, Whitehead contends, reality collapses into a plurality of mutually isolated substances:
The doctrine of the individual independence of real facts is derived from the notion that the subject-predicate form of statement conveys a truth which is metaphysically ultimate.
(PR 137)
As Whitehead sees things Leibniz has grasped the truth about the ultimate constituents of reality, but lacks the conceptuality in which to express it. Worse than this, the concepts he eventually adopts – the notions of a substratum and its properties – embody a metaphysical point of view which is the exact opposite of the one he wishes to express. These Aristotelian notions privilege permanence over flux, inertness over activity and, more importantly for the purposes of the present paper, mutual separateness over relatedness. Only with the ‘deposition of substance-quality ontology’, he contends, ‘we can reject the notion of individual substances, each with its own private world of qualities and sensations’ (PR 160).
According to Whitehead, it was precisely in order to soften this tension at the heart of his metaphysics that Leibniz developed the doctrine of pre-established harmony, according to which the monads’ perceptions have been synchronized by God. This theory enables Leibniz to hold that monads are experientially connected, while at the same time denying that they are causally related:
[Leibniz] had … on his hands two distinct points of view. One was that the final real entity is an organizing activity, fusing ingredients into a unity, so that this unity is the reality. The other point of view is that the final real entities are substances supporting qualities. The first point of view depends upon the acceptance of … relations binding together all reality. The latter is inconsistent with the reality of such relations. To combine these two distinct points of view, his monads were therefore windowless; and their passions merely mirrored the universe by the divine arrangement of a pre-established harmony.
(SMW 155)
In Whitehead's eyes, the theory of pre-established harmony is an artificial device the only purpose of which is to conceal a manifest contradiction in the system.10
Because of the strong connection between Leibniz's theory of pre-established harmony and his belief in God's existence, some readers may suspect at this point that Whitehead's rejection of that theory may be motivated by a typically modern dislike of God as an explanatory principle. As a matter of fact, Whitehead believes in God, although his God is not that of traditional Christianity; there must be, he argues in Process and Reality, a radical new way of conceiving of the Deity and his relation to the world after Hume's devastating critique in the Dialogues Concerning Natural Religion (PR 343). As the following two sections will further make clear, the reasons for his rejection of Leibniz's pre-established harmony have nothing to do with a prejudiced hostility towards theology, but are quintessentially philosophical.11
In his understanding of Leibniz's monads as substrata of change Whitehead is deeply influenced by Russell's A Critical Exposition of the Philosophy of Leibniz. Russell denounces here the metaphysical inadequacy of substance-property ontology, arguing that only two main types of metaphysical systems can be constructed on this basis – either Leibniz's theory of a plurality of independent monads or Spinoza's theory of a single encompassing Reality. Since both theories are plainly false, Russell goes on to argue, the metaphysician has to reject the subject–predicate mode of thought and devise radically new ontological categories:
Spinoza … had shown that the actual world could not be explained by means of one substance; Leibniz showed that it could not be explained by means of many substances. It became necessary, therefore, to base metaphysics on a notion other than that of substance – a task not yet accomplished.
(CEPL 126)
Whitehead repeats the argument almost verbatim in a number of places, for example in The Concept of Nature:
Some schools of philosophy, under the influence of the Aristotelian logic and the Aristotelian philosophy, endeavour to get on without admitting any relations at all except that of substance and attribute. Namely all apparent relations are to be resolvable into the concurrent existence of substances with contrasted attributes. It is fairly obvious that Leibnizian monadology is the necessary outcome of any such philosophy. If you dislike pluralism, there will be only one monad.
(CN 150)
Stated in its explicit form, Russell's critique of the substance-predicate mode of thought runs as follows:
Relations cannot be analysed in terms of the concepts of substance and property. (As a way of brief illustration, consider the statement ‘A is higher than B.’ It would seem natural to analyse it in terms of the conjunction ‘A is of height X’ and ‘A is of height Y.’ But Russell holds that this analysis is incomplete unless one also specifies what kind of relation holds between the two heights X and Y.)
Hence, if the ultimate constituents of things are bearers of properties, relations are to be condemned as unreal.
On this basis, the world can be conceived either as a single Substance (in the way of Spinoza) or as a plurality of unrelated substances (in the way of Leibniz).
Since both theories (Spinoza's Monism and Leibniz's Pluralism) are patently absurd, the doctrine that only substrata and their properties are real must be rejected as false.
In his discussion of this argument, Russell focuses upon (1) and (2). Russell is especially plagued by the question whether it is true to say that Leibniz denied that relations are real, for Leibniz does not say that they are ‘unreal’, but that they are ‘ideal’. According to Russell, Leibniz saw that relations cannot be reduced to properties. Having gone so far, he should have acknowledged relations as among the basic constituents of reality. His obstinate belief in the subject–predicate logic prevented him to do so. Torn between his own insights and his traditional Aristotelian background, he looked for a compromise solution. Hence, he ended up arguing that relations are ‘ideal’ – that is, ‘half-real’ or ‘semi-real’. For Russell this is only a subterfuge of no philosophical significance, one that is not worthy of a great logician.12
With respect to (3), Russell observes that Leibniz's Monadism and Spinoza's Monism are not logically on a par, as only Spinoza's is a coherent form of substance-metaphysics. The reason for this is that Leibniz believes his monads to be components of the very same universe. But there is no way to make sense of the idea of their unity within one world without introducing the notion of their being related. In order to achieve unity without recourse to relations, Leibniz would have to reduce all monads to adjectives of a single Substance; in this way, he would have become himself a Monist.
In due time, this early criticism of the traditional Aristotelian theory will lead to the development of a relational logic in Principia Mathematica (1910–13). The implications of Russell's early critique are developed further in Process and Reality, where Whitehead explains that the new relational logic will have to be accompanied by a new, relational metaphysics. In this book, he writes, ‘“relatedness” is dominant over “quality”’ (PR xiii).
Surprisingly, Russell says little or nothing to justify (4), the thesis that Monism and Monadism are patently false. And yet this claim is crucial if the above argument is to function as a reductio. Whitehead sees that this point stands in need of explanation. What makes the metaphysics of Spinoza and Leibniz utterly incredible, he says, is that ‘either alternative stamps experience with a certain air of illusoriness’ (PR 190).
This charge has to be understood with reference to Whitehead's theory of experience. According to him, we do constantly perceive that there are many things around us (which rules out Monism) as well as that they act upon us in a multitude of ways (which rules out causally independent monads). In conversation with one of his Harvard colleagues, Whitehead made the point thus: ‘Being tackled at Rugby, there is the Real. Nobody who hasn't been knocked down has the slightest notion of what the Real is.’13 In having such a violent experience we feel absolutely certain – with a vividness we cannot possibly resist – that there are independent causal powers taking hold of us.
The view that we have a direct apprehension of external causal powers is the view of common sense. Philosophically, it is a bold one. After Hume, philosophers have been accustomed to think of our experience of causal processes as a matter of experiencing a succession of distinct events. This may be the case when one observes two objects acting upon one another, as in Hume's favourite example of the two striking billiard balls. But things change radically when we ourselves are involved in the causal transaction. In these cases, we are able to observe the workings of causation from ‘within’. This happens, for example, when a light makes a man blink: ‘The man will explain his experience by saying, “The flash made me blink”; and if his statement be doubted, he will reply “I know it, because I felt it”’ (PR 175).
Of course, we cannot expect to have a clear and distinct sensory image of such powers in the same way in which we have a clear and distinct sensation of red when we look at a red object. But for Whitehead this only shows that Hume's analysis of ordinary human experience in terms of sensory impressions is unduly narrow. The kind of experience we have when we fall on the ground or are violently beaten with some hard object can hardly be described as an apprehension of distinct sense-impressions. A distinction must therefore be drawn between ‘perception in the mode of presentational immediacy’ (which covers awareness of sense-data) and ‘perception in the mode of causal efficacy’ (which covers awareness of causal force).
This distinction seems unobjectionable. There is really a dynamic dimension to our experience that traditional empiricist theories fail to do justice to.14 Experience is not just a matter of looking at things, but also of acting and being acted upon – we are not mere spectators, but doers as well. Still, appealing to experiences of causal efficacy as a way of refuting Leibniz's doctrine of the causal insulation of the monads may appear argumentatively weak. Can we refute the doctrine of pre-established harmony in the way Dr Johnson thought he could refute Berkeley's immaterialism – just by kicking a stone? The answer to this question is, obviously, ‘no’. Leibniz could easily grant that our experiences suggest causal efficacy, while at the same time denying that they bear witness to the existence of real causal connections.15
It must be admitted therefore that there is nothing in Whitehead's analysis of experience of the nature of a proof. The best way to read his account is to take it as an earnest invitation to consider one's experiences more closely and decide for oneself which interpretation is the more adequate.16 Looking at his theory in this way, it becomes hard to deny that his account is superior to traditional empiricist ones. Moreover, it becomes plain that he is also raising a very serious question. Given that ordinary experience inevitably suggests a constant apprehension of causal agencies, how could we ever believe Leibniz's doctrine of the unreality of causal interaction? In order to believe this doctrine, we would have to silence our most natural epistemic instincts, which is surely not an easy thing to do.
The Russell–Whitehead critique of Leibniz stands or falls with the claim that he conceived of his monads as bearers of properties/substrata of change. Russell provides little conclusive evidence in its support. Logical considerations are important in the Discourse on Metaphysics, but almost irrelevant in the Monadology and the Principles of Nature and Grace. Russell even admits that in the correspondence with De Volder Leibniz seems on the verge of adopting a process-metaphysics of events, as the monad almost dissolves into the mere series of its perceptual states.17
Whitehead seems to be unaware of this when he criticizes Leibniz's doctrine of the causal independency of the monads. In Modes of Thought, for example, he remarks:
The mere notion of transferring a quality is entirely unintelligible. Suppose that two occurrences may in fact be detached so that one of them is comprehensible without reference to the other. Then all notion of causation between them, or conditioning, becomes unintelligible.
(MT 164)
This is an allusion to that crucial passage in the Monadology in which Leibniz explains why monads cannot be affected from without:
The monads have no windows through which something can enter or leave. Accidents cannot be detached, nor can they go about outside of substances, as the sensible species of the Scholastics once did. Thus, neither substance nor accident can enter a monad from without.
(§7; AG 213–14)
The passage may be read as providing some evidence in support of the thesis that monads are for Leibniz bearers of properties as well as that there is a close connection between this Aristotelian conception and the denial of direct causal interaction. Leibniz is here concerned with that type of causal fact in which a substance A acts upon an already existing substance B, so as to produce an alteration in B. Leibniz denies that monads can be related in this way by means of the following argument:
Causation (in the sense of a substance's ability to produce an alteration in another substance's state) involves the transference of some one element from one substance A to another substance B.
On an Aristotelian substance-predicate ontology, the transferred element must be either the active substance or one of its properties.
Substances cannot become parts of other substances; for substances are simple, not complex. Hence, the transferred element will have to be a property.
During the transaction from substance A to substance B, there will be a moment in which the transferred property does not belong to either A or B. This is impossible, since properties require a substratum in which to inhere.
Hence, on an Aristotelian substance-predicate ontology, direct causal interaction between monads is impossible, as neither substances nor properties can be exchanged.
To someone convinced that causal relations are real, this reasoning will look like a further argument against the thesis (involved with premise (2)) that substances are substrata, which is precisely how Whitehead reads it.
What is noteworthy is that Whitehead does not interpret this argument, as he would be entitled to do from a logical point of view, as a reductio of premise (1) – the influx-model of causation that Leibniz derives from the late Scholastics. As a matter of fact, Whiteheads shares with Leibniz the notion that causation involves some kind of flowing in, a transference of elements from the causally active substance to the affected one. Trying to explain his rejection of direct monadic interaction to De Volder, Leibniz says: ‘Properly speaking, I don't admit the action of substances on one another, since there appears to be no way for one monad to flow into another’ (AG 176). The challenge of providing an alternative to the theory of pre-established harmony now becomes for Whitehead the question of how to make sense of monadic influx in categories different from those of substance and property.18
What remains of the monad once the concept of substratum has been rejected? Radically new ontological categories are needed and one main way to discover them is by examining the monad as this is concretely given. This is possible in a philosophy such as Whitehead's because monads are mind-like entities. Our own inner life shows what the fundamental constituents of reality are like.19
In consonance with James's account of the self in the Principles of Psychology (cf. SMW 143 ff.), Whitehead contends that our conscious life comes as a series of ‘pulses’ or ‘throbs’ of experience. The stream of consciousness is broken in a plurality of successive quanta of feeling, each of which lasts for a brief period of time. Such total moments of experience Whitehead calls ‘actual occasions’ (or, alternatively, ‘actual entities’) and offers them as substitutes for Leibniz's monads (cf. AI 177).
The new ontology Whitehead settles for is one of serially interconnected experiential events:
The soul is nothing else than the succession of my occasions of experience, extending from birth to the present moment.
(MT 163)
Needless to say, this will not suffice as an account of personal identity. A distinction needs to be drawn between the enduring self we ordinarily refer to as our ‘I’ and the fleeting momentary selves (the actual occasions) that constitute our experiential life; if one renounces the notion of substance as an enduring substratum, then the emergence of the former out of the latter stands in need of an explanation. In order to understand Whitehead's view as to the nature of causation, however, there is no need to enter into a discussion of this difficult problem.20 The only relevant question concerns the nature of the relation holding between the momentary occasions.
How are such successive occasions related? Consider our experiences when we are reading a book in a silent room and a thunder suddenly breaks in. What we experience then is not merely the sound of the thunder, but the breaking of the previous silence through it. This would not be possible if the silence of a moment ago were not still included within the novel moment in which the breaking of the thunder is experienced. Or consider our hearing of a musical melody. We could not experience any music as a flowing piece if the notes just past were not also included in our present awareness.
These examples are meant to show that there is a kind of natural ‘fusing’ within our conscious stream of its successive experiential occasions. The kind of phenomenon Whitehead is drawing our attention to here is the one Husserl calls ‘retention’, an apt term that will be used in what follows. Whitehead goes beyond Husserl in that he provides a metaphysical as opposed to a mere phenomenological account of this phenomenon. Retention is for him the way in which an immediately past occasion of experience leaves a mark upon – and thereby conditions – a novel moment of experience. In other words, Whitehead suggests that we interpret retention as a form of mental causation – as an ‘influx’ of aspects of the past moment of experience within the novel one.
In order to understand Whitehead's view correctly it is important to realize that the term ‘influx’ is not used by him in a metaphorical sense. The elements retained in the novel occasion are actual components of the previous occasion of mentality, not mere representations of them:
The present moment is constituted by the influx of the other into that self-identity which is the continued life of the immediate past within the immediacy of the present.
(AI 181)
Whitehead coined the term ‘prehension’ to designate this incorporation of aspects of our past experiences into the present one. The concept is introduced by way of a comparison with Leibniz:
[Leibniz] employed the terms ‘perception’ and ‘apperception’ for the lower and higher ways in which one monad can take account of another, namely for ways of awareness. But these terms … are all entangled with the notion of representative perception which I reject … Accordingly, on the Leibnizian model, I use the term ‘prehension’ for the general way in which the occasion of experience can include, as part of its own essence, any other entity.
(AI 234; my emphasis)
This is an intricate yet fundamental passage. In the first place, Whitehead emphasizes that retained contents are not duplicates (representative perceptions) of previous experiences, but the original experiences themselves. Secondly, he explains that the relation between two successive occasions within our stream of consciousness has a double nature. Viewed from the standpoint of the past occasion, the experiential influx involved in the phenomenon of retention is a basic form of causation. Viewed from the perspective of the novel occasion, that influx is to be regarded as an elementary form of perception. This goes at the very heart of Whitehead's critique of Leibniz, for Whitehead is putting together again in his concept of prehension what Leibniz wants to keep distinct with his theory of pre-established harmony: the capacity to perceive on the one hand, that of being directly acted upon on the other. Thirdly, Whitehead draws a comparison with Leibniz's concept of ‘perception’. This is a way of emphasizing the fact that the type of experience he calls ‘prehension’ is a primitive, low-level one. However, this is not to say that this fundamental sort of experience lacks a sense of subjective enjoyment; it solely means that it can, yet need not be made, the object of a higher order thought or experience (Leibniz's ‘apperception’).
Whitehead's account of causation in terms of the double notion of influx/prehension is a startling one. One first major problem with it is that the kind of mental determination envisaged by Whitehead seems insufficient to account for causal relations between occasions pertaining to other individuals’ experiential streams. Whitehead argues, on the contrary, that his account can be generalized to all existing occasions. Stated in Leibnizian terminology, there is no fundamental distinction between ‘immanent’ and ‘transeunt’ causation – that is, causation understood as a relation between the inner occurrences of a single monad's life and causation understood as a relation between numerically distinct monads. The principles I discover in myself have universal validity:
… in so far as we apply notions of causation to the understanding of events in nature, we must conceive these events under the general notions which apply to occasions of experience. For we can only understand causation in terms of our observation of these occasions.
(AI 184)
As a matter of fact, Whitehead thinks that we constantly retain contents originally pertaining to experiential streams other than our own, especially of the occasions of experience that constitute our body. An intimate relation holds between them and our mind, as our present experience contains those very experiences that were just felt by the several parts of the body. To feel a pain in one hand is on this view to experience (with some slight temporal delay) the very same pain that was felt by the hand. It is not that we merely localize the pain in a certain region of the body; the pain was originally felt by the hand, and only secondarily by us.
The human body, Whitehead remarks,
… is a set of occasions miraculously coordinated so as to pour its inheritance into various regions within the brain. There is thus every reason to believe that our sense of union with the body has the same original as our sense of unity with our immediate past of personal experience.
(AI 189; my emphasis)
On this understanding, the body is constituted by myriads of interconnected centres of feeling, each of which (but especially those constituting the brain) stands in a privileged causal contact with that ruling centre which is our mind. This is meant to be a more realistic version of Leibniz's theory of the mind as the body's dominant monad,21 since it vindicates the incoercible sense we all share that our mind somehow mingles with our body.
Still, on Whitehead's theory of causation there is no reason in principle why a person should not be able to retain elements from other person's minds, which sounds indeed little plausible. Not everyone will agree with this sceptical evaluation. The fact that Whitehead's theory accounts for the possibility of an interchange between occasions constituting different personal streams may be viewed by some as a promising matrix for understanding parapsychological phenomena or religious experiences.22 Whitehead seems willing to admit telepathy as a real phenomenon (cf. PR 308). And at one point he denies that knowledge of other minds is possible only by way of interpretation of our immediate sensory perceptions. ‘The claim that cognition of alien mentalities must necessarily be by means of indirect inferences from aspects of shape and of sense-objects is wholly unwarranted’ (SMW 150).
Another objection to Whitehead's account is that it seems faulty even as an explanation of immanent causation. At one point, Whitehead clarifies the nature of that link thus:
All relatedness [between occasions] … is wholly concerned with the appropriation of the dead by the living – that is, with ‘objective immortality’ whereby what is divested of its own living immediacy becomes a real component in other living immediacies of becoming.
(PR xiii–xiv)
As a way of illustration, consider the previous example of our hearing a piece of music. When we hear a melody, the notes just heard keep resonating in the present moment, yet they have lost their character of presentness (their ‘living immediacy’) and have acquired a character of pastness (‘objective immortality’). The notes are apprehended as belonging to the past – as feeble versions or echoes of the originals. This is correct from a purely phenomenological point of view, yet Whitehead also provides a metaphysical interpretation of the phenomenon of retention as involving a real entrance of the past into the present. But how could the retained experience and the experience originally felt be numerically the same, if they come with a different qualitative feel? This is impossible. One cannot divorce the appearance of an experience from what that experience is in the way required by Whitehead's account; an experience, considered as such, simply is what it feels like.23
In Whitehead's interpretation, Leibniz has grasped the truth about the ultimate principles of reality, yet he develops his theory of monads in a way that makes it both internally incoherent and empirically inadequate. While the first allegation is doubtful, the second is justified. Whitehead's bold and original attempt to ameliorate Leibniz's theory of monads by endowing them with windows, however, is not satisfactory either. Contrary to what he believes, it may not be so easy to dislodge the doctrine of pre-established harmony from Leibniz's metaphysics.
But is a Leibnizian theory of reality worthy of consideration in the contemporary philosophical climate? This question must be answered positively. Philosophers of mind are still struggling to find a place for consciousness within the physical world. The fact that human subjectivity resists incorporation within a materialist framework suggests that we lack any proper understanding of the nature of matter, rather than of mind. As Whitehead rightly noticed, Leibniz's critique of the metaphysics of early modern science is a simple yet majestic lesson in speculative thinking – one that we should take seriously even today.24 All this must be understood with a grain of salt, of course, for we cannot conclude that Leibniz's metaphysics is true as its stands. Upon all those in search of an alternative to materialism, however, the terse paragraphs of Leibniz's Monadology will hardly cease to exert a deep, thought-provoking fascination.
AG = Leibniz, G. W. Philosophical Essays, edited and translated by R. Ariew and D. Garber (Indianapolis, IN: Hackett, 1989).
CEPL = Russell, B. A Critical Exposition of the Philosophy of Leibniz: With an Appendix of Leading Passages (London: George Allen and Unwin, 1900).
CN = Whitehead, A. N. Concept of Nature [1920] (Cambridge: Cambridge University Press, 2000).
SMW = Whitehead, A. N. Science and the Modern World [1925] (New York: The Free Press, 1967).
PR = Whitehead, A. N. Process and Reality: An Essay in Cosmology [1929], corrected edition by D. R. Griffin and D. W. Sherburne (New York: The Free Press, 1978).
AI = Whitehead, A. N. Adventures of Ideas [1933] (New York: The Free Press, 1967).
MT = Whitehead, A. N. Modes of Thought [1938] (New York: The Free Press, 1969).
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1 Thanks to Pauline Phemister, Leemon B. McHenry, Jeremy Dunham, two anonymous referees and the Editor of this journal for comments on a previous version of this paper.
2 Monadistic metaphysics are also advocated in Ward (Realm of Ends or Pluralism and Theism), Carr (Theory of Monads, Cogitans Cogitata). Even absolute idealists such as F. H. Bradley took Leibniz seriously, as his theory of monads can be viewed as a pluralistic alternative to their own brand of monistic idealism; cf. Basile (‘Bradley's Metaphysics’), 189–208.
3 For a full understanding of Whitehead's metaphysics, one should also consult some of his shorter and less ambitious books, especially Religion in the Making (1926), Symbolism: Its Meaning and Effect (1927), The Function of Reason (1929), and Modes of Thought (1938).
4 For biographical information, see Lowe (Alfred North Whitehead). A critical edition of Whitehead's writings is currently in preparation; work on this project is likely to lead to the discovery of new interesting material.
5 Here is a notable example:
Leibniz inherited two thousand years of thought. He really did inherit more of the varied thoughts of his predecessors than any man before or since. His interests ranged from divinity to political philosophy, and from political philosophy to physical science. These interests were backed by profound learning. There is a book to be written, and its title should be, The Mind of Leibniz.
(MT 3)
6 The word ‘allusion’ is used here because one would search in vain for a systematic discussion of Leibniz's thought in Whitehead's works; all Whitehead offers are occasional commentaries.
7 References to Leibniz occur also in Russell's The Principles of Mathematics (1903), a book Whitehead had surely studied very carefully. Whitehead may have also read Robert Latta's Leibniz: The Monadology and Other Philosophical Writings (1898); the book contains a long introduction to Leibniz's thought as well as an anthology of texts, not just the Monadology and other metaphysical writings, but also the ‘Introduction’ to the New Essays on the Human Understanding, in which Leibniz steps forward as a phenomenologist ante litteram.
8 These two options clearly parallel the debate in Leibniz studies over whether Leibniz is a corporeal substance realist or a pure idealist. This complex debate cannot be adjudicated here. Whitehead himself does not seem to recognize that the concept of the monad can be interpreted in two distinct ways.
9 As Leibniz explains to De Volder, ‘the true notions of things are completely turned on their heads by that new philosophy which forms substances from what is only material and passive’ (AG 174).
10 It could be argued that this contradiction will necessarily reappear within Whitehead's system as well, only in a slightly different form. Since the substance-predicate mode of thought is reflected in the grammatical structure of our language, Whitehead has the problem of formulating his metaphysical vision in terms of a linguistic medium that embodies those very metaphysical commitments he explicitly rejects. Whitehead is fully aware of this difficulty; eventually, he contends, the metaphysician will have to ‘redesign’ ordinary language, so as to make it adequate to his or her own purposes (cf. PR 11). But it should be noted that this problem is not unique to Whitehead's philosophy; rather, it will arise within any system of revisionary metaphysics. On this point, see the brief but illuminating remarks in Kraus (Metaphysics of Experience), 1–8, as well as the insightful Simons (‘Metaphysical Systematics’).
11 For an accessible introduction to Whitehead's novel conception of God, as well as for those main aspects of his thought not discussed in this paper, see Sprigge (The God of Metaphysics), 409–72.
12 This aspect of Russell's critical interpretation of Leibniz's philosophy has received much attention by commentators. See, for example, Parkinson (Logic and Reality in Leibniz's Metaphysics), Ishiguro (‘Leibniz's Theory of the Ideality of Relations’), Mates (Philosophy of Leibniz), Rescher (‘Leibniz on Intermonadic Relations’), and Mugnai (Leibniz's Theory of Relations).
13 Hocking (1963), 15.
14 Leibniz does, of course, admit as much in his insistence that the nature of substance consist in force and his doctrine of appetition; his monads have a dynamic inner experiential life.
15 Analogously, Spinoza could retort that he is not denying the existence of many active beings, but solely arguing that such beings are to be regarded as ‘modes’, not as ‘substances’. At any rate, Spinoza surely did not conceive of his one Substance as a bearer of properties/substratum of change, but rather in dynamic terms; cf. Basile (Russell on Spinoza's Substance Monism).
16 An open and undogmatic mind, Whitehead suggests as much when he says: ‘It is impossible to scrutinize too carefully the character to be assigned to the datum in the act of experience’ (PR 157).
17 In a letter to De Volder Leibniz speaks of the monad as ‘something analogous to the soul, whose nature consists in a certain eternal law of the same series of change’ (AG 173). For a recent discussion of Leibniz's account of the relationship holding between a monad and the law determining the series of its changes, see Whipple (‘Structure of Leibnizian Simple Substances’).
18 Whitehead also charges Leibniz with the following contradiction:
… no reason can be given why the supreme Monad, God, is exempted from the common fate of isolation. Monads, according to this doctrine [i.e., pre-established harmony] are windowless for each other. Why have they windows towards God, and why has God windows towards them? (AI 134)
Whitehead would seem here to be guilty of some confusion. On the one hand, Leibniz's monads have no power to affect God; it is simply not true that God has ‘windows toward them’. On the other hand, in the Monadology, Leibniz explicitly ascribes to God the power to create monads, to preserve them in existence and to destroy them. But these kinds of power are very different from the sort of causal power the possession of which Leibniz denies to his monads. The influx-model of causation provides an ontological analysis of a substance's power to alter the nature of another substance; the divine powers are of a quite different order.
19 To the best of my knowledge, problems concerning the reliability of introspection are never discussed by Whitehead. In Adventures of Ideas, he raises the question ‘how the structure of experience is directly observed’ (AI 177), but fails to address it. Whitehead says that as a matter of fact he first arrived at his basic ontological concepts by way of his study of physics rather than of human psychology:
It is equally possible to arrive at this organic conception of the world [i.e., Whitehead's new metaphysics] if we start from the fundamental notions of modern physics … In fact by reason of my own studies in mathematics and mathematical physics, I did … arrive at my convictions in this way.
(SMW 152)
It is what may be called the ‘phenomenological’ approach to metaphysics, however, that is particularly at evidence in Whitehead's writings.
20 For a recent discussion, see Mingarelli (‘Is Personal Identity Something That Does Not Matter?’).
21 In the case of human beings, Whitehead does in fact speak of ‘dominant centres of feeling’ (MT 22). Differences between different types of living organisms are explained by reference to the concept of a dominant centre: ‘A vegetable is a democracy; an animal is dominated by one, or more centres of experience’ (MT 24). Inanimate objects such as chairs and rocks lack any dominant centre.
22 This view is advocated in Griffin (Unsnarling the World-Knot, 206–7).
23 Whitehead's entire critique of materialism as explained in Section 2 does indeed presuppose this phenomenological (and commonsensical) notion of experience. The following passage is long, but deserves to be quoted at full length:
The notion of life implies a certain absoluteness of self-enjoyment. This must mean a certain immediate individuality, which is a complex process of appropriating into a unity of existence the many data presented as relevant by the physical process of nature. Life implies the absolute, individual self-enjoyment arising out of this process of appropriation. I have, in my recent writings, used the word prehension to express this process of appropriation. Also I have termed each individual act of immediate self-enjoyment an occasion of experience.
(MT 150)
This makes it clear that for Whitehead an experience cannot be divorced from its qualitative aspect – that is, to experience is, literally, to ‘enjoy’. He also provides the following refutation of behaviourist accounts of human experience: ‘A consistent behaviorist cannot feel it important to refute my statements. He can only behave’ (MT 23).
24 Thomas Nagel has recently argued for the necessity to rethink our concept of nature in a way strongly reminiscent of both Leibniz and Whitehead. He contends not solely that ‘mind is not just an afterthought or an accident or an add-on, but a basic aspect of nature’ (Nagel, Mind and Cosmos, 16); he even explicitly justifies this statement by reference to the Principle of Sufficient Reason, holding in the same context that ‘pure empiricism is not enough’ (17). In Britain, Leibnizian and Whiteheadian themes have been insightfully discussed by Sprigge (Vindication of Absolute Idealism, Importance of Subjectivity). They have forcefully reappeared in Strawson (‘Realistic Monism’ and Selves: An Essay in Revisionary Metaphysics). In the USA, such views have been kept alive throughout the entire twentieth century by a relatively small yet vigorous school of process thinkers. Besides the already mentioned Griffin (Unsnarling the World-Knot), Hartshorne (Creative Synthesis and Philosophic Method, ‘Physics and Psychics’) is a philosopher particularly worthy of mention.