58 ideas
11159 | My account shows how the concept works, rather than giving an analysis [Fine,K] |
11157 | Modern philosophy has largely abandoned real definitions, apart from sortals [Fine,K] |
11171 | Defining a term and giving the essence of an object don't just resemble - they are the same [Fine,K] |
15945 | Second-order set theory just adds a version of Replacement that quantifies over functions [Lavine] |
15914 | An 'upper bound' is the greatest member of a subset; there may be several of these, so there is a 'least' one [Lavine] |
15921 | Collections of things can't be too big, but collections by a rule seem unlimited in size [Lavine] |
15937 | Those who reject infinite collections also want to reject the Axiom of Choice [Lavine] |
15936 | The Power Set is just the collection of functions from one collection to another [Lavine] |
15899 | Replacement was immediately accepted, despite having very few implications [Lavine] |
15930 | Foundation says descending chains are of finite length, blocking circularity, or ungrounded sets [Lavine] |
15920 | Pure collections of things obey Choice, but collections defined by a rule may not [Lavine] |
15898 | The controversy was not about the Axiom of Choice, but about functions as arbitrary, or given by rules [Lavine] |
15919 | The 'logical' notion of class has some kind of definition or rule to characterise the class [Lavine] |
15900 | The iterative conception of set wasn't suggested until 1947 [Lavine] |
15931 | The iterative conception needs the Axiom of Infinity, to show how far we can iterate [Lavine] |
15932 | The iterative conception doesn't unify the axioms, and has had little impact on mathematical proofs [Lavine] |
15933 | Limitation of Size: if it's the same size as a set, it's a set; it uses Replacement [Lavine] |
15913 | A collection is 'well-ordered' if there is a least element, and all of its successors can be identified [Lavine] |
15926 | Second-order logic presupposes a set of relations already fixed by the first-order domain [Lavine] |
15934 | Mathematical proof by contradiction needs the law of excluded middle [Lavine] |
15907 | Mathematics is nowadays (thanks to set theory) regarded as the study of structure, not of quantity [Lavine] |
15942 | Every rational number, unlike every natural number, is divisible by some other number [Lavine] |
15922 | For the real numbers to form a set, we need the Continuum Hypothesis to be true [Lavine] |
18250 | Cauchy gave a necessary condition for the convergence of a sequence [Lavine] |
15904 | The two sides of the Cut are, roughly, the bounding commensurable ratios [Lavine] |
15912 | Counting results in well-ordering, and well-ordering makes counting possible [Lavine] |
15949 | The theory of infinity must rest on our inability to distinguish between very large sizes [Lavine] |
15947 | The infinite is extrapolation from the experience of indefinitely large size [Lavine] |
15940 | The intuitionist endorses only the potential infinite [Lavine] |
15909 | 'Aleph-0' is cardinality of the naturals, 'aleph-1' the next cardinal, 'aleph-ω' the ω-th cardinal [Lavine] |
15915 | Ordinals are basic to Cantor's transfinite, to count the sets [Lavine] |
15917 | Paradox: the class of all ordinals is well-ordered, so must have an ordinal as type - giving a bigger ordinal [Lavine] |
15918 | Paradox: there is no largest cardinal, but the class of everything seems to be the largest [Lavine] |
15929 | Set theory will found all of mathematics - except for the notion of proof [Lavine] |
15935 | Modern mathematics works up to isomorphism, and doesn't care what things 'really are' [Lavine] |
15928 | Intuitionism rejects set-theory to found mathematics [Lavine] |
11151 | An object is dependent if its essence prevents it from existing without some other object [Fine,K] |
11152 | Essences are either taken as real definitions, or as necessary properties [Fine,K] |
11161 | Essentially having a property is naturally expressed as 'the property it must have to be what it is' [Fine,K] |
11160 | Simple modal essentialism refers to necessary properties of an object [Fine,K] |
11158 | Essentialist claims can be formulated more clearly with quantified modal logic [Fine,K] |
11167 | Metaphysical necessity is a special case of essence, not vice versa [Fine,K] |
16537 | Essence as necessary properties produces a profusion of essential properties [Fine,K, by Lowe] |
11163 | The nature of singleton Socrates has him as a member, but not vice versa [Fine,K] |
11164 | It is not part of the essence of Socrates that a huge array of necessary truths should hold [Fine,K] |
10935 | An essential property of something must be bound up with what it is to be that thing [Fine,K, by Rami] |
10936 | Essential properties are part of an object's 'definition' [Fine,K, by Rami] |
8443 | Mereological essentialism says an entity must have exactly those parts [Sosa] |
11165 | If Socrates lacks necessary existence, then his nature cannot require his parents' existence [Fine,K] |
11166 | The subject of a proposition need not be the source of its necessity [Fine,K] |
11169 | Conceptual necessities rest on the nature of all concepts [Fine,K] |
11162 | Socrates is necessarily distinct from the Eiffel Tower, but that is not part of his essence [Fine,K] |
11168 | Metaphysical necessities are true in virtue of the nature of all objects [Fine,K] |
11170 | Analytic truth may only be true in virtue of the meanings of certain terms [Fine,K] |
11172 | The meaning of 'bachelor' is irrelevant to the meaning of 'unmarried man' [Fine,K] |
8442 | What law would explain causation in the case of causing a table to come into existence? [Sosa] |
8445 | The necessitated is not always a result or consequence of the necessitator [Sosa] |
8444 | Where is the necessary causation in the three people being tall making everybody tall? [Sosa] |