Charles Sanders Peirce Quotes

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All the evolution we know of proceeds from the vague to the definite.

Charles Sanders Peirce
It is impossible not to envy the man who can dismiss reason, although we know how it must turn out at last.

Charles Sanders Peirce
Generality is, indeed, an indispensable ingredient of reality; for mere individual existence or actuality without any regularity whatever is a nullity. Chaos is pure nothing.

Charles Sanders Peirce
The essence of belief is the establishment of a habit; and different beliefs are distinguished by the different modes of action to which they give rise.

Charles Sanders Peirce
A quality is something capable of being completely embodied. A law never can be embodied in its character as a law except by determining a habit. A quality is how something may or might have been. A law is how an endless future must continue to be.

Charles Sanders Peirce
Bad reasoning as well as good reasoning is possible; and this fact is the foundation of the practical side of logic.

Charles Sanders Peirce
The next simplest feature that is common to all that comes before the mind, and consequently, the second category, is the element of Struggle.

Charles Sanders Peirce
A chemical compound might be expected to be quite as much a proposition as like an algebraic invariant.

Charles Sanders Peirce
One will meet, for example, the virtual assumption that what is relative to thought cannot be real. But why not, exactly? Red is relative to sight, but the fact that this or that is in that relation to vision that we call being red is not itself relative to sight; it is a real fact.

Charles Sanders Peirce
A hypothesis is something which looks as if it might be true and were true, and which is capable of verification or refutation by comparison with facts.

Charles Sanders Peirce
There is here no need of throwing out "extreme cases." Far from that, it is precisely in the extreme cases that the power and beauty of the magic eyeglass is most apparent and most marvellous. Let me take back the word "magic," though; for the reasonableness of it is just its crowning charm.

Charles Sanders Peirce
If an opinion can eventually go to the determination of a practical belief, it, in so far, becomes itself a practical belief; and every proposition that is not pure metaphysical jargon and chatter must have some possible bearing upon practice.

Charles Sanders Peirce
There never was a sounder logical maxim of scientific procedure than Ockham's razor: Entia non sunt multiplicanda praeter necessitatem. That is to say; before you try a complicated hypothesis, you should make quite sure that no simplification of it will explain the facts equally well.

Charles Sanders Peirce
Mathematics is purely hypothetical: it produces nothing but conditional propositions.

Charles Sanders Peirce
The truth is, that common-sense, or thought as it first emerges above the level of the narrowly practical, is deeply imbued with that bad logical quality to which the epithet metaphysical is commonly applied; and nothing can clear it up but a severe course of logic.

Charles Sanders Peirce
In those sciences of measurement which are the least subject to error — meteorology, geodesy, and metrical astronomy — no man of self-respect ever now states his results, without affixing to it its probable error; and if this practice is not followed in other sciences it is because in those the probable errors are too vast to be estimated.

Charles Sanders Peirce
Do you call it doubting to write down on a piece of paper that you doubt? If so, doubt has nothing to do with any serious business. But do not make believe; if pedantry has not eaten all the reality out of you, recognize, as you must, that there is much that you do not doubt, in the least. Now that which you do not at all doubt, you must and do regard as infallible, absolute truth.

Charles Sanders Peirce
The final upshot of thinking is the exercise of volition, and of this thought no longer forms a part; but belief is only a stadium of mental action, an effect upon our nature due to thought, which will influence future thinking.

Charles Sanders Peirce
The word "God," so "capitalised" (as we Americans say), is the definable proper name, signifying Ens necessarium; in my belief Really creator of all three Universes of Experience.

Charles Sanders Peirce
The tendency to regard continuity, in the sense in which I shall define it, as an idea of prime importance in philosophy conveniently may be be termed synechism. The present paper is intended chiefly to show what synechism is, and what it leads to.

Charles Sanders Peirce
Time with its continuity logically involves some other kind of continuity than its own. Time, as the universal form of change, cannot exist unless there is something to undergo change, and to undergo a change continuous in time, there must be a continuity of changeable qualities.

Charles Sanders Peirce
Fourth, this supreme law, which is celestial and living harmony, does not so much as demand that the special ideas shall surrender their peculiar arbitrariness and caprice entirely; for that would be self-destructive. It only requires that they influence and be influenced by one another.

Charles Sanders Peirce
The ordinary logic has a great deal to say about genera and species, or in our nineteeth century dialect, about classes. Now a class is a set of objects comprising all that stand to one another in a special relation of similarity. But where ordinary logic talks of classes the logic of relatives talks of systems. A system is a set of objects comprising all that stands to one another in a group of connected relations. Induction according to ordinary logic rises from the contemplation of a sample of a class to that of a whole class; but according to the logic of relatives it rises from the comtemplation of a fragment of a system to the envisagement of the complete system.

Charles Sanders Peirce
It is terrible to see how a single unclear idea, a single formula without meaning, lurking in a young man's head, will sometimes act like an obstruction … in an artery, hindering the nutrition of the brain, and condemning its victim to pine away in the fullness of his intellectual vigor and in the midst of intellectual plenty.

Charles Sanders Peirce
Now, let there be an indefinite succession of these inferential acts of comparative perception; and it is plain that the last moment will contain objectively the whole series. Let there be, not merely an indefinite succession, but a continuous flow of inference through a finite time; and the result will be a mediate objective consciousness of the whole time in the last moment. In this last moment, the whole series will be recognized, or known as known before.

Charles Sanders Peirce
To suppose universal laws of nature capable of being apprehended by the mind and yet having no reason for their special forms, but standing inexplicable and irrational, is hardly a justifiable position. Uniformities are precisely the sort of facts that need to be accounted for. That a pitched coin should sometimes turn up heads and sometimes tails calls for no particular explanation; but if it shows heads every time, we wish to know how this result has been brought about. Law is par excellence the thing that wants a reason.

Charles Sanders Peirce
Third, consider the insistency of an idea. The insistency of a past idea with reference to the present is a quantity which is less, the further back that past idea is, and rises to infinity as the past idea is brought up into coincidence with the present.

Charles Sanders Peirce
Indeed, even this last moment will be recognized like the rest, at least, be just beginning to be so.

Charles Sanders Peirce
Accordingly, time logically supposes a continuous range of intensity of feeling. It follows then, from the definition of continuity, that when any particular kind of feeling is present, an infinitesimal continuum of all feelings differing infinitesimally from that, is present.

Charles Sanders Peirce
Second, in the presence of this continuity of feeling, nominalistic maxims appear futile. There is no doubt about one idea affecting another, when we can directly perceive the one generally modified and shaping itself into the other. Nor can there any longer be any difficulty about one idea resembling another, when we can pass along the continuous field of quality from one to the other and back again to the point which we had marked.

Charles Sanders Peirce