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Single Idea 4739

[filed under theme 1. Philosophy / F. Analytic Philosophy / 3. Analysis of Preconditions ]

Full Idea

Necessary and sufficient conditions are usually expressed by "if and only if" (abbr. "iff"), where "if" is the sufficient condition, and "only if" is the necessary condition.

Gist of Idea

In "if and only if" (iff), "if" expresses the sufficient condition, and "only if" the necessary condition

Source

Pascal Engel (Truth [2002], §1.1)

Book Ref

Engel,Pascal: 'Truth' [Acumen 2002], p.14

A Reaction

'I take my umbrella if and only if it is raining' (oh, and if I'm still alive). There may be other necessary conditions than the one specified. Oh, and I take it if my wife slips it into my car…

Related Idea

Idea 3891 If p entails q, then p is sufficient for q, and q is necessary for p [Scruton]

The 16 ideas from Pascal Engel

4739 In "if and only if" (iff), "if" expresses the sufficient condition, and "only if" the necessary condition [Engel]
4737 Are truth-bearers propositions, or ideas/beliefs, or sentences/utterances? [Engel]
4738 The coherence theory says truth is an internal relationship between groups of truth-bearers [Engel]
4744 We can't explain the corresponding structure of the world except by referring to our thoughts [Engel]
4745 Any coherent set of beliefs can be made more coherent by adding some false beliefs [Engel]
4746 Pragmatism is better understood as a theory of belief than as a theory of truth [Engel]
4750 The redundancy theory gets rid of facts, for 'it is a fact that p' just means 'p' [Engel]
4751 Maybe there is no more to be said about 'true' than there is about the function of 'and' in logic [Engel]
4752 Deflationism must reduce bivalence ('p is true or false') to excluded middle ('p or not-p') [Engel]
4753 Deflationism seems to block philosophers' main occupation, asking metatheoretical questions [Engel]
4755 Deflationism cannot explain why we hold beliefs for reasons [Engel]
4754 Our beliefs are meant to fit the world (i.e. be true), where we want the world to fit our desires [Engel]
4759 Mental states as functions are second-order properties, realised by first-order physical properties [Engel]
4762 The Humean theory of motivation is that beliefs may be motivators as well as desires [Engel]
4763 'Evidentialists' say, and 'voluntarists' deny, that we only believe on the basis of evidence [Engel]
4764 We cannot directly control our beliefs, but we can control the causes of our involuntary beliefs [Engel]