Bibliography

Division III. Substantial Study of Logic. Chapter VI. The Essence of Reasoning

A belief is a habit; but it is a habit of which we are conscious.

There are two meanings of the words possible and necessary which are of special interest to the logician more than to other men. These refer to the states of information in which we are supposed to know nothing, except the meanings of words, and their consequences, and in which we are supposed to know everything. These I term essential and substantial possibility, respectively: and of course necessity has similar varieties. That is essentially or logically possible which a person who knows no facts, though perfectly au fait at reasoning and well-acquainted with the words involved, is unable to pronounce untrue. The essentially or logically necessary is that which such a person knows is true. For instance, he would not know whether there was or was not such an animal as a basilisk, or whether there are any such things as serpents, cocks, and eggs; but he would know that every basilisk there may be has been hatched by a serpent from a cock’s egg. That is essentially necessary; because that is what the word basilisk means.

That is essentially or logically possible which a person who knows no facts, though perfectly au fait at reasoning and well-acquainted with the words involved, is unable to pronounce untrue.

… a symbol, in itself, is a mere dream; it does not show what it is talking about. It needs to be connected with its object. For that purpose, an index is indispensable. No other kind of sign will answer the purpose. That a word cannot in strictness of speech be an index is evident from this, that a word is general - it occurs often, and every time it occurs, it is the same word, and if it has any meaning as a word, it has the same meaning every time it occurs; while an index is essentially an affair of here and now, its office being to bring the thought to a particular experience, or series of experiences connected by dynamical relations. A meaning is the associations of a word with images, its dream exciting power. An index has nothing to do with meanings; it has to bring the hearer to share the experience of the speaker by showing what he is talking about.

…inference has at least two elements: the one is the suggestion of one idea by another according to the law of association, while the other is the carrying forward of the asserting element of judgment, the holding for true, from the first judgment to the second. That these two things suffice [to] constitute inference I do not say…

An inference is a passage from one belief to another; but not every such passage is an inference. If noticing my ink is bluish, I cast my eye out of the window and my mind being awakened to color remark particularly a poppy, that is no inference. Or if without casting my eye out of the window, I call to mind the green tinge of Niagara or the blue of the Rhone, that is no inference. In inference one belief not only follows after another, but follows from it. [—]

If a belief is produced for the first time directly after a judgment or colligation of judgments and is suggested by them, then that belief must be considered as the result of and as following from those judgments. The idea which is the matter of the belief is suggested by the idea in those judgments according to some habit of association, and the peculiar character of believing the idea really is so, is derived from the same element in the judgments. Thus, inference has at least two elements: the one is the suggestion of one idea by another according to the law of association, while the other is the carrying forward of the asserting element of judgment, – the holding for true, – from the first judgment to the second. That these two things suffice to constitute inference I do not say.

…I use the word information to mean a state of knowledge, which may range from total ignorance of everything except the meanings of words up to omniscience; and by informational I mean relative to such a state of knowledge.

The actual calling to mind of the substance of a belief, not as personal to ourselves, but as holding good, or true, is a judgment.

The habit or disposition according to which the conclusion is inferred from the premise is of the nature of a belief; and the proposition expressing this belief is called the leading principle.

Because every speech must contain two elements one indicative, the other symbolic, there is a logical foundation for the separation of a proposition into a subject and predicate. The subject is the part containing the indicative constituent, and from which it cannot conveniently be detached, while the predicate is the part purely symbolic.

Because every speech must contain two elements one indicative, the other symbolic, there is a logical foundation for the separation of a proposition into a subject and predicate. The subject is the part containing the indicative constituent, and from which it cannot conveniently be detached, while the predicate is the part purely symbolic.

The terms, substantial necessity and substantial possibility […] refer to supposed information of the present in the present, including among the objects known all existing laws as well as special facts. In this sense, everything in the present which is possible is also necessary, and there is no present contingent. But we may suppose there are “future contingents.” Many men are so cocksure that necessity governs everything that they deny that there is anything substantially contingent. But it will be shown in the course of this treatise that they are unwarrantably confident, that wanting omniscience we ought to presume there may be things substantially contingent, and further that there is overwhelming evidence that such things there are.

…the substantially possible refers to the information of a person who knows everything now existing, whether particular fact or law, together with all their consequences. [—] The terms, substantial necessity and substantial possibility […] refer to supposed information of the present in the present, including among the objects known all existing laws as well as special facts.

It seems certainly the truest statement for most languages to say that a symbol is a conventional sign which being attached to an object signifies that that object has certain characters. But a symbol, in itself, is a mere dream; it does not show what it is talking about. It needs to be connected with its object. For that purpose, an index is indispensable. No other kind of sign will answer the purpose. That a word cannot in strictness of speech be an index is evident from this, that a word is general - it occurs often, and every time it occurs, it is the same word, and if it has any meaning as a word, it has the same meaning every time it occurs; while an index is essentially an affair of here and now. A word is the same word every time it occurs and if it has any meaning has always the same meaning; but this and that have different applications every time they occur.