Charles S. Peirce
On Time and Thought
MS 216 (Robin 379): Writings 3, 72-75
8 March 1873
Any mind which has the power of investigation, and which therefore passes from doubt to belief, must have its ideas follow after one another in time. And if there is to be any distinction of a right and a wrong method of investigation, it must have some control over the process. So that there must be such a thing as the production of one idea from another which was previously in the mind. This is what takes place in reasoning, where the conclusion is brought into the mind by the premises. We may imagine a mind which should reason and never know that it reasoned; never being aware that its conclusion was a conclusion, or was derived from anything which went before. For such a mind there might be a right and a wrong method of thinking; but it could not be aware that there was such a distinction, nor criticise in any degree its own operations. To be capable of logical criticism, the mind must be aware that one idea is determined by another. Now when this happens after the first idea comes the second. There is a process which can only take place in a space of time; but an idea is not present to the mind during a space of timeat least not during a space of time in which this idea is replaced by another; for when the moment of its being present is passed, it is no longer in the mind at all. Therefore, the fact that one idea succeeds another is not a thing which in itself can be present to the mind, any more than the experiences of a whole day or of a year can be said to be present to the mind. It is something which can be lived through; but not be present in any one instant; and therefore, which can not be present to the mind at all; for nothing is present but the passing moment, and what it contains. The only way therefore in which we can be aware of a process of inference, or of any other process, is by its producing some idea in us. Not only therefore is it necessary that one idea should produce another; but it is also requisite that a mental process should produce an idea. These three things must be found in every logical mind: First, ideas; second, determinations of ideas by previous ideas; third, determinations of ideas by previous processes. And nothing will be found which does not come under one of these three heads. The determination of one thing by another, implies that the former not only follows after the latter, but follows after it according to a general rule, in consequence of which, every such idea would be followed by such a second one. There can therefore be no determination of one idea by another except so far as ideas can be distributed into classes, or have some resemblances. But how can one idea resemble another? An idea can contain nothing but what is present to the mind in that idea. Two ideas exist at different times; consequently what is present to the mind in one is present only at that time, and is absent at the time when the other idea is present. Literally, therefore, one idea contains nothing of another idea; and in themselves they can have no resemblance. They certainly do not resemble one another except so far as the mind can detect a resemblance; for they exist only in the mind, and are nothing but what they are thought to be. Now when each is present to the mind the other is not in the mind at all. No reference to it is in the mind, and no idea of it is in the mind. Neither idea therefore when it is in the mind, is thought to resemble the other which is not present in the mind. And an idea can not be thought, except when it is present in the mind. And, therefore, one idea can not be thought to resemble another, strictly speaking. In order to escape from this paradox, let us see how we have been led into it. Causation supposes a general rule, and therefore similarity. Now so long as we suppose that what is present to the mind at one time is absolutely distinct from what is present to the mind at another time, our ideas are absolutely individual, and without any similarity. It is necessary, therefore, that we should conceive a process as present to the mind. And this process consists of parts existing at different times and absolutely distinct. And during the time that one part is in the mind, the other is not in the mind. To unite them, we have to suppose that there is a consciousness running through the time. So that of the succession of ideas which occur in a second of time, there is but one consciousness, and of the succession of ideas which occurs in a minute of lime there is another consciousness, and so on, perhaps indefinitely. So that there may be a consciousness of the events that happened in a whole day or a whole life time. According to this, two parts of a process separated in timethough they are absolutely separate, in so far as there is a consciousness of the one, from which the other is entirely excludedare yet so far not separate, that there is a more general consciousness of the two together. This conception of consciousness is something which takes up time. It seems forced upon us to escape the contradictions which we have just encountered. And if consciousness has a duration, then there is no such thing as an instantaneous consciousness; but all consciousness relates to a process. And no thought, however simple, is at any instant present to the mind in its entirety, but it is something which we live through or experience as we do the events of a day. And as the experiences of a day are made up of the experiences of shorter spaces of time so any thought whatever is made up of more special thoughts which in their turn are themselves made up by others and so on indefinitely. It may indeed very likely be that there is some minimum space of time within which in some sense only an indivisible thought can exist and as we know nothing of such a fact at present we may content ourselves with the simpler conception of an indefinite continuity in consciousness. It will easily be seen that when this conception is once grasped the process of the determination of one idea by another becomes explicable. What is present to the mind during the whole of an interval of time is something generally consisting of what there was in common in what was present to the mind during the parts of that interval. And this may be the same with what is present to the mind during any interval of time; or if not the same, at least similarthat is, the two may be such that they have much in common. These two thoughts which are similar may be followed by others that are similar and according to a general law by which every thought similar to either of these is followed by another similar to those by which they are followed. If a succession of thoughts have any thing in common this may belong to every part of these thoughts however minute, and therefore it may be said to be present at every instant. This element of consciousness which belongs to a whole only so far as it belongs to its parts is termed the matter of thought. There is besides this a causation running through our consciousness by which the thought of any one moment determines the thought of the next moment no matter how minute these moments may be. And this causation is necessarily of the nature of a reproduction; because if a thought of a certain kind continues for a certain length of lime as it must do to come into consciousness the Immediate effect produced by this causality must also be present during the whole time, so that it is a part of that thought. Therefore when this thought ceases, that which continues after it by virtue of this action is a part of the thought itself. In addition to this there must be an effect produced by the following of one idea after a different idea otherwise there would be no process of inference except that of the reproduction of the premises.