If then the historian has no direct or empirical knowledge of his facts, and no transmitted or testimoniary knowledge of them, what kind of knowledge has he: in other words, what must the historian do in order that he may know them? My historical review of the idea of history has resulted in the emergence of an answer to this question: namely, that the historian must re-enact the past in his own mind.[...]
The contention that an act cannot happen twice because the flow of consciousness carries it away is thus false. Its falsity arises from an ignoratio elenchi. So far as experience consists of mere consciousness, of sensations and feelings pure and simple, it is true. But an act of thought is not a mere sensation or feeling. It is knowledge, and knowledge is something more than immediate consciousness. The process of knowledge is therefore not a mere flow of consciousness. A person whose consciousness was a mere succession of states, by whatever name these states are called, could have no knowledge whatever. He could not remember his own past states, for (even granting that his states are connected together by certain psychological laws, ex hypothesi to him unknowable) he would not remember being burnt but would only fear the fire. Nor could he perceive the world around him; he would fear, but would not recognize that which he feared as the fire. Least of all would he, or anyone else, know that his consciousness was the mere succession of states that it is alleged to be. If, then, mere consciousness is a succession of states, thought is an activity by which that succession is somehow arrested so as to be apprehended in its general structure: something for which the past is not dead and gone, but can be envisaged together with the present and compared with it. Thought itself is not involved in the flow of immediate consciousness; in some sense it stands outside that flow.
Thought can never be mere object. To know someone else’s activity of thinking is possible only on the assumption that this same activity can be re-enacted in one’s own mind. In that sense, to know ‘what someone is thinking’ (or ‘has thought’) involves thinking it for oneself. To reject this conclusion means denying that we’ have any right to speak of acts of thought at all, except such as take place in our own minds, and embracing the doctrine that my mind is the only one that exists.[...]
It has shown that an act of thought can be not only performed at an instant but sustained over a lapse of time; not only sustained, but revived; not only revived in the experience of the same mind but (on pain of solipsism) re-enacted in another’s. But this does not prove the possibility of history. For that, we must be able not only to re-enact another’s thought but also to know that the thought we are re-enacting is his. But so far as we re-enact it, it becomes our own; it is merely as our own that we perform it and are aware of it in the performance; it has become subjective, but for that very reason it has ceased to be objective; become present, and therefore ceased to be past.[...]
The act of thinking, then, is not only subjective but objective as well. It is not only a thinking, it is something that can be thought about. But, because (as I have already tried to show) it is never merely objective, it requires to be thought about in a peculiar way, a way only appropriate to itself. It cannot be set before the thinking mind as a ready-made object, discovered as something independent of that mind and studied as it is in itself, in that independence. It can never be studied ‘objectively’, in the sense in which ‘objectively’ excludes ‘subjectively’. It has to be studied as it actually exists, that is to say, as an act. And because this act is subjectivity (though not mere subjectivity) or experience, it can be studied only in its own subjective being, that is, by the thinker whose activity or experience it is. This study is not mere experience or consciousness, not even mere self-consciousness: it is self-knowledge. Thus the act of thought in becoming subjective does not cease to be objective; it is the object of a self-knowledge which differs from mere consciousness in being self-consciousness or awareness, and differs from being mere self-consciousness in being self-knowledge: the critical study of one’s own thought, not the mere awareness of that thought as one’s own.
Here it is possible to answer a tacit question which was left open when I said that a person who performs an act of knowing can also know that he ‘is performing or has performed’ that act. Which is it? Clearly, the first: for the act of thought has to be studied as it actually exists, that is, as an act. But this does not exclude the second. We have already seen that if mere experience is conceived as a flow of successive states, thought must be conceived as something that can apprehend the structure of this flow and the forms of succession which it exhibits: that is, thought is able to think the past as well as the present. Where thought studies the activity of thinking itself, therefore, it is equally able to study past acts of thinking and compare them with the present act. But there is a difference between the two cases. If I now think about a feeling which I had in the past, it may be true that thinking about it occasions, or else perhaps depends for its possibility on the independent occurrence of, an echo of that feeling in the present: that, for example, I could not think of the anger I once felt except so far as I now experience at least a faint vibration of anger in my mind. But whether this is true or not, the actual past anger of which I am thinking is past and gone; that does not reappear, the stream of immediate experience has carried it away for ever; at most there reappears something like it. The gap of time between my present thought and its past object is bridged not by the survival or revival of the object, but only by the power of thought to overleap such a gap; and the thought which does this is memory.
If, on the contrary, what I think about is a past activity of thought, for example a past philosophical inquiry of my own, the gap is bridged from both sides. To think at all about that past activity of thought, I must revive it in my own mind, for the act of thinking can be studied only as an act. But what is so revived is not a mere echo of the old activity, another of the same kind; it is that same activity taken up again and re-enacted, perhaps in order that, doing it over again under my own critical inspection, I may detect in it false steps of which critics have accused me. In thus re-thinking my past thought I am not merely remembering it. I am constructing the history of a certain phase of my life: and the difference between memory and history is that whereas in memory the past is a mere spectacle, in history it is re-enacted in present thought. So far as this thought is mere thought, the past is merely re-enacted; so far as it is thought about thought, the past is thought of as being re-enacted, and my knowledge of myself is historical knowledge. The history of myself is thus not memory as such, but a peculiar case of memory. Certainly, a mind which could not remember could not have historical knowledge. But memory as such is only the present thought of past experience as such, be that experience what it may; historical knowledge is that special case of memory where the object of present thought is past thought, the gap between present and past being bridged but only by the power of present thought to think of the past, but also by the power of past thought to reawaken itself in the present.