Suppose we have a chain of argument which takes the form: Since A is B, and B is C, and C is D, it follows A is D. In such an argument, though 'B is C' and 'C is D' may both be perfectly true, yet if 'A is B' be false, we have no more reason for asserting A is D than if all three were false. It does not, indeed, follow that A is D is false; nor does it follow that no other arguments would prove it to be true. But it does follow that, so far as this argument goes, it is the barest supposition, without the least bit of evidence. I propose to attack a proposition which seems to me to stand in this relation to the conclusion 'Reality is spiritual.' I do not propose to dispute that 'Reality is spiritual;' I do not deny that there may be reasons for thinking that it is: but I do propose to show that one reason upon which, to the best of my judgment, all other arguments ever used by Idealists depend is false. These other arguments may, for all I shall say, be eminently ingenious and true; they are very many and various, and different Idealists use the most different arguments to prove the same most important conclusions. Some of these may be sufficient to prove that B is C and C is D; but if, as I shall try to show, their 'A is B' is false the conclusion A is D remains a pleasant supposition. I do not deny that to suggest pleasant and plausible suppositions may be the proper function of philosophy: but I am assuming that the name Idealism can only be properly applied where there is a certain amount of argument, intended to be cogent.
The subject of this paper is, therefore, quite uninteresting. Even if I prove my point, I shall have proved nothing about the Universe in general. Upon the important question whether Reality is or is not spiritual my argument will not have the remotest bearing. I shall only attempt to arrive at the truth about a matter, which is in itself quite trivial and insignificant, and from which, so far as I can see and certainly so far as I shall say, no conclusions can be drawn about any of the subjects about which we most want to know. The only importance I can claim for the subject I shall investigate is that it seems to me to be a matter upon which not Idealists only, but all philosophers and psychologists also, have been in error, and from their erroneous view of which they have inferred (validly or invalidly) their most striking and interesting conclusions. And that it has even this importance I cannot hope to prove. If it has this importance, it will indeed follow that all the most striking results of philosophy—Sensationalism. Agnosticism and Idealism alike—have, for all that has hitherto been urged in their favour, no more foundation than the supposition that a chimera lives in the moon. It will follow that, unless new reasons never urged hitherto can be found, all the most important philosophic doctrines have as little claim to assent as the most superstitious beliefs of the lowest savages. Upon the question what we have reason to believe in the most interesting matters, I do therefore think that my results will have an important bearing; but I cannot too clearly insist that upon the question whether these beliefs are true they will have none whatever.
The trivial proposition which I propose to dispute is this: that esse is percipi. This is a very ambiguous proposition, but, in some sense or other, it has been very widely held. That it is, in some sense, essential to Idealism, I must for the present merely assume. What I propose to show is that, in all the senses ever given to it, it is false.
But, first of all, it may be useful to point out briefly in what relation I conceive it to stand to Idealistic arguments. That wherever you can truly predicate esse you can truly predicate percipi, in some sense or other, is, I take it, a necessary step In all arguments, properly to be called Idealistic, and, what is more, in all arguments hitherto offered for the Idealistic conclusion. If esse is percipi, this is at once equivalent to saying that whatever is, is experienced; and this, again, is equivalent, in a sense, to saying that whatever is, is something mental. But this is not the sense in which the Idealist conclusion must maintain that Reality is mental. The Idealist conclusion is that esse is percipere; and hence, whether esse be percipi or not, a further and different discussion is needed to show whether or not it is also percipere. And again, even if esse be percipere, we need a vast quantity of further argument to show that what has esse has also those higher mental qualities which are denoted by spiritual. This is why I said that the question I should discuss, namely, whether or not esse is percipi, must be utterly insufficient either to prove or to disprove that reality is spiritual. But, on the other hand, I believe that every argument ever used to show that reality is spiritual has inferred this (validly or invalidly) from 'esse is percipere' as one of its premisses; and that this again has never been pretended to be proved except by use of the premiss that esse is percipi. The type of argument used for the latter purpose is familiar enough. It is said that since whatever is, is experienced, and since some things are which are not experienced by the individual, these must at least form part of some experience. Or again that, since an object necessarily implies a subject, and since the whole world must be an object, we must conceive it to belong to some subject or subjects, in the same sense in which whatever is the object of our experience belongs to us. Or again, that, since thought enters into the essence of all reality, we must conceive behind it, in it, or as its essence, a spirit akin to ours, who think: that 'spirit greets spirit' in its object. Into the validity of these inferences I do not propose to enter: they obviously require a great deal of discussion. I only desire to point out that, however correct they may be, yet if esse is not percipi, they leave us as far from a proof that reality is spiritual, as if they were all false too.
But now: Is esse percipi? There are three very ambiguous terms in this proposition, and I must begin by distinguishing the different things that may be meant by some of them.
And first with regard to percipi. This term need not trouble us long at present. It was, perhaps, originally used to mean 'sensation' only; but I am not going to be so unfair to modern Idealists—the only Idealists to whom the term should now be applied without qualification—as to hold that, if they say esse is percipi, they mean by percipi sensation only. On the contrary I quite agree with them that, if esse be percipi at all, percipi must be understood to include not sensation only, but that other type of mental fact, which is called 'thought '; and, whether esse be percipi or not, I consider it to be the main service of the philosophic school, to which modern Idealists belong, that they have insisted on distinguishing 'sensation' and 'thought' and on emphasising the importance of the latter. Against Sensationalism and Empiricism they have maintained the true view. But the distinction between sensation and thought need not detain us here. For, in whatever respects they differ, they have at least this in common, that they are both forms of consciousness or, to use a term that seems to be more in fashion just now, they are both ways of experiencing. Accordingly, whatever esse is percipi may mean, it does at least assert that whatever is, is experienced. And since what I wish to maintain is, that even this is untrue, the question whether it be experienced by way of sensation or thought or both is for my purpose quite irrelevant. If it be not experienced at all, it cannot be either an object of thought or an object of sense. It is only if being involves 'experience' that the question, whether it involves sensation or thought or both, becomes important. I beg, therefore, that percipi may be understood, in what follows, to refer merely to what is common to sensation and thought. A very recent article states the meaning of esse is percipi with all desirable clearness in so far as percipi is concerned.
'I will undertake to show,' says Mr. Taylor,[1] 'that what makes [any piece of fact] real can be nothing but its presence as an inseparable aspect of a sentient experience.' I am glad to think that Mr. Taylor has been in time to supply me with so definite a statement that this is the ultimate premiss of Idealism. My paper will at least refute Mr. Taylor's Idealism, if it refutes anything at all: for I shall undertake to show that what makes a thing real cannot possibly be its presence as an inseparable aspect of a senient experience.
But Mr. Taylor's statement though clear, I think, with regard to the meaning of percipi is highly ambiguous in other respects. I will leave it for the present to consider the next ambiguity in the statement: Esse is percipi. What does the copula mean? What can be meant by saying that Esse is percipi? There are just three meanings, one or other of which such a statement must have, if it is to be true; and of these there is only one which it can have, if it is to be important. (1) The statement may be meant to assert that the word 'esse' is used to signify nothing either more or less than the word 'percipi': that the two words are precise synonyms: that they are merely different names for one and the same thing: that what is meant by esse is absolutely identical with what is meant by percipi. I think I need not prove that the principle esse is percipi is not thus intended merely to define a word; nor yet that, if it were, it would be an extremely bad definition. But if it does not mean this, only two alternatives remain. The second is (2) that what is meant by esse, though not absolutely identical with what is meant by percipi, yet includes the latter as a part of its meaning. If this were the meaning of 'esse is percipi,' then to say that a thing was real would not be the same thing as to say that it was experienced. That it was real would mean that it was experienced and something else besides: 'being experienced' would be analytically essential to reality, but would not be the whole meaning of the term. From the fact that a thing was real we should be able to infer, by the law of contradiction, that it was experienced; since the latter would be part of what is meant by the former. But, on the other hand, from the fact a thing was experienced we should not be able to infer that it was real; since it would not follow from the fact that it had one of the attributes essential to reality, that it also had the other or others. Now, if we understand esse is percipi in this second sense, we must distinguish three different things which it asserts. First of all, it gives a definition of the word 'reality,' asserting that word stands for a complex whole, of which what is meant by 'percipi' forms a part. And secondly it asserts that 'being experienced' forms a part of a certain whole. Both these propositions may be true, and at all events I do not wish to dispute them. I do not, indeed, think that the word 'reality' is commonly used to include 'percipi': but I do not wish to argue about the meaning of words. And that many things which are experienced are also something else—that to be experienced forms part of certain wholes, is, of course, indisputable. But what I wish to point out is, that neither of these propositions is of any importance, unless we add to them a third. That 'real' is a convenient name for a union of attributes which sometimes occurs, it could not be worth any one's while to assert: no inferences of any importance could be drawn from such an assertion. Our principle could only mean that when a thing happens to have percipi as well as the other qualities included under esse, it has percipi: and we should never be able to infer that it was experienced, except from a proposition which already asserted that it was both experienced and something else. Accordingly, if the assertion that percipi forms part of the whole meant by reality is to have any importance, it must mean that the whole is organic, at least in this sense, that the other constituent or constituents of it cannot occur without percipi, even if percipi can occur without them. Let us call these other constituents x. The proposition that esse includes percipi, and that therefore from esse percipi can be inferred, can only be important if it is meant to assert that percipi can be inferred from x. The only importance of the question whether the whole esse includes the part percipi rests therefore on the question whether the part x is necessarily connected with the part percipi. And this is (3) the third possible meaning of the assertion esse is percipi: and, as we now see, the only important one. Esse is percipi asserts that wherever you have x you also have percipi that whatever has the property x also has the property that it is experienced. And this being so, it will be convenient if, for the future, I may be allowed to use the term 'esse' to denote x alone. I do not wish thereby to beg the question whether what we commonly mean by the word 'real' does or does not include percipi as well as x. I am quite content that my definition of 'esse' to denote x, should be regarded merely as an arbitrary verbal definition. Whether it is so or not, the only question of interest is whether from x percipi can be inferred, and I should prefer to be able to express this in the form: can percipi be inferred from esse? Only let it be understood that when I say esse, that term will not for the future include percipi: it denotes only that x, which Idealists, perhaps rightly, include along with percipi under their term esse. That there is such an x they must admit on pain of making the proposition an absolute tautology; and that from this x percipi can be inferred they must admit, on pain of making it a perfectly barren analytic proposition. Whether x done should or should not be called esse is not worth a dispute: what is worth dispute is whether percipi is necessarily connected with x.
We have therefore discovered the ambiguity of the copula in esse is percipi, so far as to see that this principle asserts two distinct terms to be so related, that whatever has the one, which I call esse, has also the property that it is experienced. It asserts a necessary connexion between esse on the one hand and percipi on the other; these two words denoting each a distinct term, and esse denoting a term in which that denoted by percipi is not included. We have, then in esse is percipi, a necessary synthetic proposition which I have undertaken to refute. And I may say at once that, understood as such, it cannot be refuted. If the Idealist chooses to assert that it is merely a self-evident truth, I have only to say that it does not appear to me to be so. But I believe that no Idealist ever has maintained it to be so. Although this—that two distinct terms are necessarily related—is the only sense which 'esse is percipi' can have if it is to be true and important, it can have another sense, if it is to be an important falsehood. I believe that Idealists all hold this important falsehood. They do not perceive that Esse is percipi must, if true, be merely a self-evident synthetic truth: they either identify with it or give as a reason for it another proposition which must be false because it is self-contradictory. Unless they did so, they would have to admit that it was a perfectly unfounded assumption; and if they recognised that it was unfounded, I do not think they would maintain its truth to be evident. Esse is percipi, in the sense I have found for it, may indeed be true; I cannot, refute it: but if this sense were clearly apprehended, no one, I think, would believe that it was true.
Idealists, we have seen, must assert that whatever is experienced, is necessarily so. And this doctrine they commonly express by saying that 'the object of experience is inconceivable apart from the subject.' I have hitherto been concerned with pointing out what meaning this assertion must have, if it is to be an important truth. I now propose to show that it may have an important meaning, which must be false, because it is self-contradictory.