On the Old Saw: That May Be Right in Theory But It Won’t Work in Practice?

A set of rules, even practical rules, is called a theory if the rules are conceived as principles of a certain generality and are abstracted from a multitude of conditions which necessarily influence their application. Conversely, we do not give the name practice to every activity, only to that accomplishment of an end which is thought to follow certain generally conceived principles of procedure.

However complete the theory may be, it is obvious that between theory and practice there must be a link, a connection and transition from one to the other. To the intellectual concept that contains the rule, an act of judgment must be added whereby the practitioner distinguishes whether or not something is an instance of the rule. And since we cannot always lay down rules for our judgment to observe in subsumption (as this would go on ad infinitum), there may be theoreticians who, for lack of judgment, can never be practical: physicians or jurists, for example, who have been well schooled but do not know what to do when they are summoned to a consultation.

But even where we find this natural gift, there may be a lack of premises. The theory may be incomplete, perhaps to be supplemented only by additional experiments and experiences from which the trained physician, agriculturist, or economist can and should abstract new rules of his own, to complete his theory. Thus, when the theory did not work too well in practice, the fault lay, not in the theory, but rather in there being not enough theory which a man should have learned from experience; and which is true theory even though he cannot express it or, as a teacher, expound it systematically in general propositions, and thus he cannot claim to be a theoretical physician, agriculturist, etc.

Accordingly, no man claiming to be practically versed in a science can disdain its theory without exposing himself as an ignoramus in his field. It is the belief of such a man that he can get farther than theory might take him by fumbling with experiments and experiences without specific principles for organizing them (which properly constitutes what we call “theory”) and without an overall conception of his business (which, when pursued methodically, is called a “system”).

And yet, when an ignorant individual calls theory unnecessary and dispensable in his supposed practice, this is not as unbearable as when a know-it-all admits its academic value (as a mere mental exercise, perhaps) while asserting that in practice things look altogether different, that with one’s emergence from school into the world comes an awareness of having pursued empty ideals and philosophical dreams—in a word, that what sounds good in theory is invalid in practice. (Which is often put this way: that some proposition or other does apply in thesi, but not in hypothesi.) Now, if an empirical machinist said of general mechanics, or an artilleryman of the mathematical doctrine of ballistics, that the theory is nicely thought out but not at all valid in practice because the experience of applying it yields very different results, one would simply laugh at them. For if the first were to consider the theory of friction, and the second that of air resistance—that is, if they were to add more theory—their theories would conform very well to experience. Still, matters are altogether different with a theory that concerns objects which can be observed, and with one concerning objects represented merely by concepts (such as the objects of mathematics and those of philosophy). Although from the standpoint of reason the latter objects may indeed and unimpeachably be thought, they are perhaps not given at all; they may be nothing but empty ideas that in practice are put either to no use at all or to a detrimental use. In such cases, therefore, that old saw might be perfectly appropriate.

In a theory based on the concept of duty, however, there need be no concern about empty ideality. For the pursuit of a certain effect of our will would be no duty if the effect were not also possible in experience (whether conceived as complete, or as constantly approaching completion); and this is the only kind of theory we are discussing in the present essay. About this theory the philosophically scandalous pretense is not infrequently advanced—that what may be true in it is still invalid in practice. And this pretense is advanced in a tone of lofty disdain full of presumption to have reason itself reformed by experience in the area which reason deems its highest honor, and with the sapient conceit to see farther and more clearly with the eyes of a mole, fixed upon experience, than with the eyes of a being that was made to stand erect and to behold the heavens.

This maxim, grown very common in our talkative, actionless times, does most harm when it refers to questions of ethics (to moral or legal duty). For these are matters of the canon of reasons (in the practical realm), where the value of practice depends entirely on its appropriateness to the underlying theory. All is lost if empirical and therefore accidental conditions of the application of the law are turned into conditions of the law itself, and thus a practice calculated for an outcome probable in line with past experience is made master of the self-existing theory.

I divide this essay according to the three standpoints from which a gentleman bold enough thus to pronounce on theories and systems usually judges his object. That is, in three qualities: 1. as a private person yet a man of business, 2. as a statesman, and 3. as a man in the world (or, a world citizen generally). These three persons are agreed to have at the man of the academy, who works on theory in their behalf and to their benefit; imagining that they know better, they mean to banish him to his academy (illa se iactet in aula!—Let him shine in the lecture hall!), as a pedant unfit for practice and a mere obstacle in the way of their experienced wisdom.

Accordingly, we shall present the relationship of theory and practice in three parts: first, in morality in general (with regard to the welfare of each human being); second, in politics (with respect to the welfare of states); third, in a cosmopolitan perspective (regarding the welfare of the human race as a whole and assuming that progress in that direction is made in the generational sequence of all times to come). For reasons apparent from the essay itself, the subtitles will express the relationship of theory and practice in morality, in constitutional law, and in international law.