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 …

I think we may safely say that the studies preliminary to the construction of a great theory should be at least as deliberate and thorough as those that are preliminary to the building of a dwelling-house.

When a man is about to build a house, what a power of thinking he has to do, before he can safely break ground!

Of the fifty or hundred systems of philosophy that have been advanced at different times of the world's history, perhaps the larger number have been, not so much results of historical evolution, as happy thoughts which have accidently …

A pair of statements may be taken conjunctively or disjunctively; for example, "It lightens and it thunders," is conjunctive, "It lightens or it thunders" is disjunctive. Each such individual act of connecting a pair of statements is a new …

All the monads except as serve as intermediaries for the connections have distinctive designations.

These objects are commonly called points; but to remove all notion of space relations, it may be better to name them monads.

Now, to say that a lot of objects is finite, is the same as to say that if we pass through the class from one to another we shall necessarily come round to one of those individuals already passed; that is, if every one of the lot is in any …

The actual world cannot be distinguished from a world of imagination by any description. Hence the need of pronoun and indices, and the more complicated the subject the greater the need of them.

in contemplating a painting, there is a moment when we lose the consciousness that it is not the thing, the distinction of the real and the copy disappears, and it is for the moment a pure dream, — not any particular existence, and yet not …

I call a sign which stands for something merely because it resembles it, an icon. Icons are so completely substituted for their objects as hardly to be distinguished from them.

Of this nature are all natural signs and physical symptoms. I call such a sign an index, a pointing finger being the type of the class. The index asserts nothing; it only says "There!" It takes hold of our eyes, as it were, and forcibly …

If the sign were not related to its object except by the mind thinking of them separately, it would not fulfil the function of a sign at all.

Such signs are always abstract and general, because habits are general rules to which the organism has become subjected.

A sign is in a conjoint relation to the thing denoted and to the mind.

Any character or proposition either concerns one subject, two subjects, or a plurality of subjects.

By an object, I mean anything that we can think, i.e. anything we can talk about.

The definition of definition is at bottom just what the maxim of pragmatism expresses.

It has never been in my power to study anything, — mathematics, ethics, metaphysics, gravitation, thermodynamics, optics, chemistry, comparative anatomy, astronomy, psychology, phonetics, economics, the history of science, whist, men and …

I define a Sign as anything which is so determined by something else, called its Object, and so determines an effect upon a person, which effect I call its Interpretant, that the latter is thereby mediately determined by the former.

a cooperation of three subjects, such as a sign, its object, and its interpretant, this tri-relative influence not being in any way resolvable into actions between pairs.

It is important to understand what I mean by semiosis.

You are of all my friends the one who illustrates pragmatism in its most needful forms. You are a jewel of pragmatism.

It is the man of science, eager to have his every opinion regenerated, his every idea rationalized, by drinking at the fountain of fact, and devoting all the energies of his life to the cult of truth, not as he understands it, but as he …