50 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] |
| 18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
| 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] |
| 3884 | The pragmatist does not really have a theory of truth [Scruton] |
| 18789 | Intuitionist logic looks best as natural deduction [Mares] |
| 18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
| 18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
| 18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
| 18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
| 18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
| 18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
| 18782 | The connectives are studied either through model theory or through proof theory [Mares] |
| 18783 | Many-valued logics lack a natural deduction system [Mares] |
| 18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
| 18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
| 3907 | Could you be intellectually acquainted with numbers, but unable to count objects? [Scruton] |
| 3908 | If maths contains unprovable truths, then maths cannot be reduced to a set of proofs [Scruton] |
| 18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
| 3906 | If possible worlds are needed to define properties, maybe we should abandon properties [Scruton] |
| 13804 | A property is essential iff the object would not exist if it lacked that property [Forbes,G] |
| 13805 | Properties are trivially essential if they are not grounded in a thing's specific nature [Forbes,G] |
| 13808 | A relation is essential to two items if it holds in every world where they exist [Forbes,G] |
| 13806 | Trivially essential properties are existence, self-identity, and de dicto necessities [Forbes,G] |
| 13807 | A property is 'extraneously essential' if it is had only because of the properties of other objects [Forbes,G] |
| 13809 | One might be essentialist about the original bronze from which a statue was made [Forbes,G] |
| 3888 | Hume assumes that necessity can only be de dicto, not de re [Scruton] |
| 13810 | The source of de dicto necessity is not concepts, but the actual properties of the thing [Forbes,G] |
| 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] |
| 18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
| 3882 | Wittgenstein makes it impossible to build foundations from something that is totally private [Scruton] |
| 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] |