Charles S. Peirce
Notes for Lectures on Logic
to be given 1st term 1870-71
MS 171 (Robin 587): Writings 3, 439-440
1. Truth belongs to signs, particularly, and to thoughts as signs. [Note 1: True sign is that which means as something really is.] Truth is the agreement of a meaning with a reality.
2. The meaningto lektonis the respect in which signs which translate each other are conceived to agree. It is something independent of how the thing signified really is and depends only on what is conveyed to whoever interprets the sign rightly. Whether this meaning is something out of the mind or only in the mind or nothing at all (as the Stoics who originated the term lekton maintained) is a question which cannot affect the propriety of the definition of truth here given.
3. The meaning must be carefully distinguished from the sign itself and from the thing signified.
A real thing is something whose characters are independent of how any representation represents it to be.
Independent, therefore, of how any number of men think it to be. Idealism does not falsify definition.
The next question is in what sense can two things as incommensurable as a meaning and a reality be said to agree.
The point of contact is the living mind which is affected in a similar way by real things and by their signs. And this is the only possible point of contact.
I say "a certain thing is blue." The image of blueness this excites in the mind is not a copy of any blueness in the sentence. Therefore, even if the sensation of blue be a copy of an external blue in the blue thing, there can be no other agreement between the sentence and the thing than that they convey the same notion to the mind.
4. [Note 2: The doctrine of individuality should come in here.] The agreement between the meaning of a sign and a reality consists in the former's exciting the same notion in the mind that the reality does.
This is obviously much too vague and shows us the necessity of beginning with a systematic analysis of the conception of a sign.
But before proceeding to such an analysis we may make a certain use of this vague proposition.
This shows that we must come to an idealistic doctrine concerning truth. We must mean by how things are, how we are affected by them.
Yet there is a distinction between a true and false idea, also. Then by the truth concerning a thing we do not mean how any man is affected by a thing.
Nor how a majority is affected.
But how a man would be affected after sufficient experience, discussion, and reasoning.
5. [Note 3: The doctrine of contradiction should come before this.] That there is a truth about everything implies that sufficient experience, discussion, and reasoning would lead a man to a certain opinion. [Note 4: Final cause acts in history of opinion.]
Then since to say that a thing is so and so is the same as to say that it is true that it is so and so it follows that
6. The Real thing is the ultimate opinion about it.
About it, that is, about the ultimate opinion, but not involving the reflection that the opinion is itself that ultimate one and is the real thing. Indeed this opinion is in one sense an ideal inasmuch as more experience and reasoning may always be had.