Combining Texts

All the ideas for 'Letters to Edward Stillingfleet', 'Elements of Mathematical Logic' and 'Reason, Emotions and Good Life'

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4 ideas

4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic

8942	Lukasiewicz's L3 logic has three truth-values, T, F and I (for 'indeterminate') [Lukasiewicz, by Fisher]
	Full Idea: In response to Aristotle's sea-battle problem, Lukasiewicz proposed a three-valued logic that has come to be known as L3. In addition to the values true and false (T and F), there is a third truth-value, I, meaning 'indeterminate' or 'possible'.
	From: report of Jan Lukasiewicz (Elements of Mathematical Logic [1928], 7.I) by Jennifer Fisher - On the Philosophy of Logic
	A reaction: [He originated the idea in 1917] In what sense is the third value a 'truth' value? Is 'I don't care' a truth-value? Or 'none of the above'? His idea means that formalization doesn't collapse when things get obscure. You park a few propositions under I.

9. Objects / D. Essence of Objects / 3. Individual Essences

15990	Every individual thing which exists has an essence, which is its internal constitution [Locke]
	Full Idea: I take essences to be in everything that internal constitution or frame for the modification of substance, which God in his wisdom gives to every particular creature, when he gives it a being; and such essences I grant there are in all things that exist.
	From: John Locke (Letters to Edward Stillingfleet [1695], Letter 1), quoted by Simon Blackburn - Quasi-Realism no Fictionalism
	A reaction: This is the clearest statement I have found of Locke's commitment to essences, for all his doubts about whether we can know such things. Alexander says (ch.13) Locke was reacting against scholastic essence, as pertaining to species.

11. Knowledge Aims / B. Certain Knowledge / 1. Certainty

15994	If it is knowledge, it is certain; if it isn't certain, it isn't knowledge [Locke]
	Full Idea: What reaches to knowledge, I think may be called certainty; and what comes short of certainty, I think cannot be knowledge.
	From: John Locke (Letters to Edward Stillingfleet [1695], Letter 2), quoted by Simon Blackburn - Quasi-Realism no Fictionalism
	A reaction: I much prefer that fallibilist approach offered by the pragmatists. Knowledge is well-supported belief which seems (and is agreed) to be true, but there is a small shadow of doubt hanging over all of it.

20. Action / C. Motives for Action / 3. Acting on Reason / a. Practical reason

4316	Either all action is rational, or reason dominates, or reason is only concerned with means [Cottingham]
	Full Idea: We can distinguish rational exclusivism (all activity is guided by reason - Plato and Spinoza), rational hegemonism (all action is dominated by reason), and rational instrumentalism (reason assesses means rather than ends - Hume).
	From: John Cottingham (Reason, Emotions and Good Life [2000])
	A reaction: The idea that reason is the only cause of actions seems deeply implausible, but I strongly resist Hume's instrumental approach. Action without desire is not a contradiction.