Digital Companion to C. S. Peirce
1901 | Pearson's Grammar of Science: Annotations on the First Three Chapters | EP 2:62; CP 8.144

Our logically initial data are percepts. Those percepts are undoubtedly purely psychical, altogether of the nature of thought. They involve three kinds of psychical elements, their qualities of feelings, their reaction against my will, and their generalizing or associating element. But all that we find out afterward.

1902 | Minute Logic: Chapter II. Prelogical Notions. Section I. Classification of the Sciences | MS [R] 426:23

It is essential, at the very threshold of logic, to distinguish between a percept, which is what the senses perceive, and which is an object of study for the intellect, and a perceptual fact, which the understanding perceives in the percept, and which is the first fruit of observation. Photographs, even when they show no more than the eye can see, are most valuable in sciences of observation; they are stored up percepts. But they in no degree enable us to dispose with scientific descriptions, which are records of perceptual facts, the basis of all else in science.

1902 | Minute Logic: Chapter II. Prelogical Notions. Section I. Classification of the Sciences (Logic II) | CP 1.253

The direct percept, as it first appears, appears as forced upon us brutally. It has no generality; and without generality there can be no psychicality. Physicality consists in being under the governance of physical, i.e., efficient, causes, psychicality in being under the governance of psychical, i.e., of final, causes. The percept brutally forces itself upon us; thus it appears under a physical guise. It is quite ungeneral, even antigeneral – in its character as percept; and thus it does not appear as psychical. The psychical, then, is not contained in the percept.

1902 | Minute Logic: Chapter II. Section II. Why Study Logic? | CP 2.142

The percepts, could I make sure what they were, constitute experience proper, that which I am forced to accept. But whether they are experience of the real world, or only experience of a dream, is a question which I have no means of answering with absolute certainty.

1903 | Harvard Lectures on Pragmatism: Lecture IV. The Seven Systems of Metaphysics | EP 2:191; CP 5.115

Even after the percept is formed there is an operation which seems to me to be quite uncontrollable. It is that of judging what it is that the person perceives. A judgment is an act of formation of a mental proposition combined with an adoption of it or act of assent to it. A percept on the other hand is an image or moving picture or other exhibition.

1903 | Telepathy | CP 7.619-21

Let us say that, as I sit here writing, I see on the other side of my table, a yellow chair with a green cushion. That will be what psychologists term a “percept” (res percepta). They also frequently call it an “image.” With this term I shall pick no quarrel. Only one must be on one’s guard against a false impression that it might insinuate. Namely, an “image” usually means something intended to represent, – virtually professing to represent, – something else, real or ideal. So understood, the word “image” would be a misnomer for a percept. The chair I appear to see makes no professions of any kind, essentially embodies no intentions of any kind, does not stand for anything. It obtrudes itself upon my gaze; but not as a deputy for anything else, not “as” anything. It simply knocks at the portal of my soul and stands there in the doorway.

It is very insistent, for all its silence. It would be useless for me to attempt to pooh-pooh it, and say, “Oh come, I don’t believe in the chair.” I am forced to confess that it appears. Not only does it appear, but it disturbs me, more or less. I cannot think the appearance is not there, nor dismiss it as I would a fancy. I can only get rid of it by an exertion of physical force.

It is a forceful thing. Yet it offers no reason, defence, nor excuse for its presence. It does not pretend to any right to be there. It silently forces itself upon me.

1903 | Telepathy | CP 7.625

…two utterly different kinds of elements go to compose any percept. In the first place, there are the qualities of feeling or sensation, each of which is something positive and sui generis, being such as it is quite regardless of how or what anything else is. On account of this self-sufficiency, it is convenient to call these the elements of “Firstness.” In the percept, these elements of Firstness are perceived to be connected in definite ways. A visual percept of a chair has a definite shape. If it is yellow with a green cushion, that is quite different from being green with a yellow cushion. These connectives are directly perceived, and the perception of each of them is a perception at once of two opposed objects, – a double awareness. In respect to each of these connections, one part of the percept appears as it does relatively to a second part. Hence, it is convenient to call them elements of “Secondness.” The vividness with which a percept stands out is an element of secondness; because the percept is vivid in proportion to the intensity of its effect upon the perceiver. These elements of secondness bring with them the peculiar singleness of the percept. This singleness consists in a double definiteness. For on the one hand, the percept contains no blank gaps which, in representing it, we are free to fill as we like. What I mean will be seen if we consider any knowledge we can have of the future. I heard somebody say that the Brooklyn bridge would fall some day. The only way in which he could even think he knew that would be by knowing that any bridge I might select that should be constructed in a certain way would fall. There is no such universality about the percept. It is quite individual. On the other hand, the definiteness of the percept is of a perfectly explicit kind. In any knowledge of the past something is, as it were, held in reserve. There is an indicated gap which we are not free to fill but which further information may fill. We know that the Sphinx was made by some king of Egypt. But what one? The percept, however, exhibits itself in full. These two kinds of definiteness, first, that the percept offers no range of freedom to anybody who may undertake to represent it, and secondly, that it reserves no freedom to itself to be one way or another way, taken together, constitute that utter absence of “range” which is called the singularity, or singleness, of the percept, the one making it individual and the other positive. The percept is, besides, whole and undivided. It has parts, in the sense that in thought it can be separated; but it does not represent itself to have parts. In its mode of being as a percept it is one single and undivided whole.

1904 | Reason's Conscience: A Practical Treatise on the Theory of Discovery; Wherein logic is conceived as Semeiotic | HP 2:809-10; MS 693:378-80

Knowledge takes its rise from the percept, which is the object perceived in a single act of perceiving. [—] The percepts are not knowledge, but are the starting points of knowledge, in which many percepts and possibilities of percepts are worked up into propositions.

1904-10-03 | Letters to William James | CP 8.300

Percepts are signs for psychology; but they are not so for phenomenology.

1905 | Notes on Portions of Hume's "Treatise on Human Nature" | MS [R] 939:29

The first cognition which we can recognize is a percept. Different people are different; but to me a percept is very much like a moving picture, accompanied by sounds and other sensations. I am also conscious of its being there in spite of me, so that I resist it, that is a sort of inertia tending to object to surprise is overcome in perceiving. It is there by brute force.

1906 | Prolegomena to an Apology for Pragmaticism | CP 4.539

A fact of Immediate Perception is not a Percept, nor any part of a Percept; a Percept is a Seme, while a fact of Immediate Perception or rather the Perceptual Judgment of which such fact is the Immediate Interpretant, is a Pheme that is the direct Dynamical Interpretant of the Percept, and of which the Percept is the Dynamical Object, and is with some considerable difficulty (as the history of psychology shows), distinguished from the Immediate Object, though the distinction is highly significant.

1907 | Pragmatism | EP 2:419

percepts, that is, complex feelings endowed with compulsiveness

1909 | Significs and Logic | EP 2:510 n. 10

…the Signs of the Reality of an appearance are, 1st, its Insistency (of which Sign its Vividness is again a Sign), 2nd, its sameness to all witnesses, except for differences that are but corroborative, and 3rd, its physical reactions; and the Reality is that which these Signs go toward proving; so that we have only to ask what they do prove, and the answer to that question will be the Definition of a Percept.

What they prove as thoroughly as any Actual Fact can be proved, is that genuine Percepts represent, both in their qualities and their occasions, Facts concerning Matter as independent of themselves, the Perceptions.