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Single Idea 2112

[filed under theme 10. Modality / D. Knowledge of Modality / 1. A Priori Necessary ]

Full Idea

There are two kinds of truths: of reasoning and of facts. Truths of reasoning are necessary and their opposites impossible. Facts are contingent and their opposites possible. A necessary truth is known by analysis.

Gist of Idea

Truths of reason are known by analysis, and are necessary; facts are contingent, and their opposites possible

Source

Gottfried Leibniz (Monadology [1716], §33)

Book Ref

Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.184

The 22 ideas with the same theme [knowing what must be, just through thought]:

2301 We know by thought that what is done cannot be undone [Descartes]
12553 Some of our ideas contain relations which we cannot conceive to be absent [Locke]
2112 Truths of reason are known by analysis, and are necessary; facts are contingent, and their opposites possible [Leibniz]
17079 Proofs of necessity come from the understanding, where they have their source [Leibniz]
19432 Intelligible truth is independent of any external things or experiences [Leibniz]
23461 Kant thought worldly necessities are revealed by what maths needs to make sense [Kant, by Morris,M]
14710 Necessity is always knowable a priori, and what is known a priori is always necessary [Kant, by Schroeter]
16256 For Kant metaphysics must be necessary, so a priori, so can't be justified by experience [Kant, by Maudlin]
5524 Maths must be a priori because it is necessary, and that cannot be derived from experience [Kant]
23495 The tautologies of logic show the logic of language and the world [Wittgenstein]
9169 A statement can be metaphysically necessary and epistemologically contingent [Putnam]
15101 Once you give up necessity as a priori, causal necessity becomes the main type of necessity [Shoemaker]
4728 Kripke separates necessary and a priori, proposing necessary a posteriori and contingent a priori examples [Kripke, by O'Grady]
16990 A priori = Necessary because we imagine all worlds, and we know without looking at actuality? [Kripke]
15228 Necessity and contingency are separate from the a priori and the a posteriori [Harré/Madden]
2526 Philosophers regularly confuse failures of imagination with insights into necessity [Dennett]
12428 Many necessities are inexpressible, and unknowable a priori [Kitcher]
20476 If the necessary is a priori, so is the contingent, because the same evidence is involved [Casullo]
13956 Kripke is often taken to be challenging a priori insights into necessity [Chalmers]
9598 Modal thinking isn't a special intuition; it is part of ordinary counterfactual thinking [Williamson]
21621 We can't infer metaphysical necessities to be a priori knowable - or indeed knowable in any way [Williamson]
4719 Maybe developments in logic and geometry have shown that the a priori may be relative [O'Grady]