77 ideas
3879 | Philosophy aims to provide a theory of everything [Scruton] |
3891 | If p entails q, then p is sufficient for q, and q is necessary for p [Scruton] |
16325 | Analysis rests on natural language, but its ideal is a framework which revises language [Halbach] |
16292 | An explicit definition enables the elimination of what is defined [Halbach] |
16307 | Don't trust analogies; they are no more than a guideline [Halbach] |
3894 | We may define 'good' correctly, but then ask whether the application of the definition is good [Scruton] |
3883 | A true proposition is consistent with every other true proposition [Scruton] |
16330 | Truth-value 'gluts' allow two truth values together; 'gaps' give a partial conception of truth [Halbach] |
16339 | Truth axioms prove objects exist, so truth doesn't seem to be a logical notion [Halbach] |
16324 | Any definition of truth requires a metalanguage [Halbach] |
16293 | Traditional definitions of truth often make it more obscure, rather than less [Halbach] |
16301 | If people have big doubts about truth, a definition might give it more credibility [Halbach] |
3884 | The pragmatist does not really have a theory of truth [Scruton] |
16297 | Semantic theories avoid Tarski's Theorem by sticking to a sublanguage [Halbach] |
16337 | Disquotational truth theories are short of deductive power [Halbach] |
16322 | CT proves PA consistent, which PA can't do on its own, so CT is not conservative over PA [Halbach] |
16294 | Axiomatic truth doesn't presuppose a truth-definition, though it could admit it at a later stage [Halbach] |
16326 | The main semantic theories of truth are Kripke's theory, and revisions semantics [Halbach] |
16311 | To axiomatise Tarski's truth definition, we need a binary predicate for his 'satisfaction' [Halbach] |
16318 | Compositional Truth CT has the truth of a sentence depending of the semantic values of its constituents [Halbach] |
16299 | Gödel numbering means a theory of truth can use Peano Arithmetic as its base theory [Halbach] |
16340 | Truth axioms need a base theory, because that is where truth issues arise [Halbach] |
16305 | We know a complete axiomatisation of truth is not feasible [Halbach] |
16313 | A theory is 'conservative' if it adds no new theorems to its base theory [Halbach, by PG] |
16315 | The Tarski Biconditional theory TB is Peano Arithmetic, plus truth, plus all Tarski bi-conditionals [Halbach] |
16314 | Theories of truth are 'typed' (truth can't apply to sentences containing 'true'), or 'type-free' [Halbach] |
16327 | Friedman-Sheard is type-free Compositional Truth, with two inference rules for truth [Halbach] |
16329 | Kripke-Feferman theory KF axiomatises Kripke fixed-points, with Strong Kleene logic with gluts [Halbach] |
16332 | The KF theory is useful, but it is not a theory containing its own truth predicate [Halbach] |
16331 | The KF is much stronger deductively than FS, which relies on classical truth [Halbach] |
16319 | Compositional Truth CT proves generalisations, so is preferred in discussions of deflationism [Halbach] |
16320 | Some say deflationism is axioms which are conservative over the base theory [Halbach] |
16338 | Deflationism says truth is a disquotation device to express generalisations, adding no new knowledge [Halbach] |
16317 | The main problem for deflationists is they can express generalisations, but not prove them [Halbach] |
16316 | Deflationists say truth is just for expressing infinite conjunctions or generalisations [Halbach] |
16335 | In Strong Kleene logic a disjunction just needs one disjunct to be true [Halbach] |
16334 | In Weak Kleene logic there are 'gaps', neither true nor false if one component lacks a truth value [Halbach] |
16309 | Every attempt at formal rigour uses some set theory [Halbach] |
16333 | The underestimated costs of giving up classical logic are found in mathematical reasoning [Halbach] |
16310 | A theory is some formulae and all of their consequences [Halbach] |
16342 | You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [Halbach] |
16341 | Normally we only endorse a theory if we believe it to be sound [Halbach] |
16344 | Soundness must involve truth; the soundness of PA certainly needs it [Halbach] |
16347 | Many new paradoxes may await us when we study interactions between frameworks [Halbach] |
16336 | The liar paradox applies truth to a negated truth (but the conditional will serve equally) [Halbach] |
3907 | Could you be intellectually acquainted with numbers, but unable to count objects? [Scruton] |
16321 | The compactness theorem can prove nonstandard models of PA [Halbach] |
16343 | The global reflection principle seems to express the soundness of Peano Arithmetic [Halbach] |
16312 | To reduce PA to ZF, we represent the non-negative integers with von Neumann ordinals [Halbach] |
16308 | Set theory was liberated early from types, and recent truth-theories are exploring type-free [Halbach] |
3908 | If maths contains unprovable truths, then maths cannot be reduced to a set of proofs [Scruton] |
16345 | That Peano arithmetic is interpretable in ZF set theory is taken by philosophers as a reduction [Halbach] |
3906 | If possible worlds are needed to define properties, maybe we should abandon properties [Scruton] |
16346 | Maybe necessity is a predicate, not the usual operator, to make it more like truth [Halbach] |
3888 | Hume assumes that necessity can only be de dicto, not de re [Scruton] |
3903 | The conceivable can't be a test of the possible, if there are things which are possible but inconceivable [Scruton] |
3897 | Epistemology is about the justification of belief, not the definition of knowledge [Scruton] |
3881 | In the Cogito argument consciousness develops into self-consciousness [Scruton] |
3887 | Maybe our knowledge of truth and causation is synthetic a priori [Scruton] |
3901 | Touch only seems to reveal primary qualities [Scruton] |
3885 | We only conceive of primary qualities as attached to secondary qualities [Scruton] |
3910 | If primary and secondary qualities are distinct, what has the secondary qualities? [Scruton] |
3899 | The representational theory says perceptual states are intentional states [Scruton] |
3898 | My belief that it will rain tomorrow can't be caused by its raining tomorrow [Scruton] |
3880 | Logical positivism avoids scepticism, by closing the gap between evidence and conclusion [Scruton] |
3878 | Why should you believe someone who says there are no truths? [Scruton] |
3892 | Every event having a cause, and every event being determined by its cause, are not the same [Scruton] |
3911 | The very concept of a substance denies the possibility of mutual interaction and dependence [Scruton] |
16298 | We need propositions to ascribe the same beliefs to people with different languages [Halbach] |
3882 | Wittgenstein makes it impossible to build foundations from something that is totally private [Scruton] |
468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
3896 | Any social theory of morality has the problem of the 'free rider', who only pretends to join in [Scruton] |
3886 | Membership is the greatest source of obligation [Scruton] |
3895 | The categorical imperative is not just individual, but can be used for negotiations between strangers [Scruton] |
3890 | 'Cause' used to just mean any valid explanation [Scruton] |
3904 | Measuring space requires no movement while I do it [Scruton] |
3905 | 'Existence' is not a predicate of 'man', but of the concept of man, saying it has at least one instance [Scruton] |