66 ideas
12274 | Begin examination with basics, and subdivide till you can go no further [Aristotle] |
12260 | Dialectic starts from generally accepted opinions [Aristotle] |
12291 | There can't be one definition of two things, or two definitions of the same thing [Aristotle] |
12292 | Definitions are easily destroyed, since they can contain very many assertions [Aristotle] |
12272 | We describe the essence of a particular thing by means of its differentiae [Aristotle] |
12279 | The differentia indicate the qualities, but not the essence [Aristotle] |
12283 | In definitions the first term to be assigned ought to be the genus [Aristotle] |
12289 | The genera and the differentiae are part of the essence [Aristotle] |
12261 | Differentia are generic, and belong with genus [Aristotle] |
12263 | 'Genus' is part of the essence shared among several things [Aristotle] |
12285 | The definition is peculiar to one thing, not common to many [Aristotle] |
18951 | For scientific purposes there is a precise concept of 'true-in-L', using set theory [Putnam] |
10170 | While true-in-a-model seems relative, true-in-all-models seems not to be [Reck/Price] |
18953 | Modern notation frees us from Aristotle's restriction of only using two class-names in premises [Putnam] |
18949 | The universal syllogism is now expressed as the transitivity of subclasses [Putnam] |
18952 | '⊃' ('if...then') is used with the definition 'Px ⊃ Qx' is short for '¬(Px & ¬Qx)' [Putnam] |
18958 | In type theory, 'x ∈ y' is well defined only if x and y are of the appropriate type [Putnam] |
10166 | ZFC set theory has only 'pure' sets, without 'urelements' [Reck/Price] |
18954 | Before the late 19th century logic was trivialised by not dealing with relations [Putnam] |
18956 | Asserting first-order validity implicitly involves second-order reference to classes [Putnam] |
18962 | Unfashionably, I think logic has an empirical foundation [Putnam] |
18961 | We can identify functions with certain sets - or identify sets with certain functions [Putnam] |
10175 | Three types of variable in second-order logic, for objects, functions, and predicates/sets [Reck/Price] |
18955 | Having a valid form doesn't ensure truth, as it may be meaningless [Putnam] |
11261 | Puzzles arise when reasoning seems equal on both sides [Aristotle] |
10165 | 'Analysis' is the theory of the real numbers [Reck/Price] |
12273 | Unit is the starting point of number [Aristotle] |
18959 | Sets larger than the continuum should be studied in an 'if-then' spirit [Putnam] |
10174 | Mereological arithmetic needs infinite objects, and function definitions [Reck/Price] |
10164 | Peano Arithmetic can have three second-order axioms, plus '1' and 'successor' [Reck/Price] |
10172 | Set-theory gives a unified and an explicit basis for mathematics [Reck/Price] |
10167 | Structuralism emerged from abstract algebra, axioms, and set theory and its structures [Reck/Price] |
10169 | Relativist Structuralism just stipulates one successful model as its arithmetic [Reck/Price] |
10179 | There are 'particular' structures, and 'universal' structures (what the former have in common) [Reck/Price] |
10181 | Pattern Structuralism studies what isomorphic arithmetic models have in common [Reck/Price] |
10182 | There are Formalist, Relativist, Universalist and Pattern structuralism [Reck/Price] |
10168 | Formalist Structuralism says the ontology is vacuous, or formal, or inference relations [Reck/Price] |
10178 | Maybe we should talk of an infinity of 'possible' objects, to avoid arithmetic being vacuous [Reck/Price] |
10176 | Universalist Structuralism is based on generalised if-then claims, not one particular model [Reck/Price] |
10177 | Universalist Structuralism eliminates the base element, as a variable, which is then quantified out [Reck/Price] |
10171 | The existence of an infinite set is assumed by Relativist Structuralism [Reck/Price] |
12267 | There are ten categories: essence, quantity, quality, relation, place, time, position, state, activity, passivity [Aristotle] |
12282 | An individual property has to exist (in past, present or future) [Aristotle] |
12264 | An 'accident' is something which may possibly either belong or not belong to a thing [Aristotle] |
18957 | Nominalism only makes sense if it is materialist [Putnam] |
10173 | A nominalist might avoid abstract objects by just appealing to mereological sums [Reck/Price] |
18950 | Physics is full of non-physical entities, such as space-vectors [Putnam] |
12280 | Genus gives the essence better than the differentiae do [Aristotle] |
13269 | In the case of a house the parts can exist without the whole, so parts are not the whole [Aristotle] |
12284 | Everything that is has one single essence [Aristotle] |
12262 | An 'idion' belongs uniquely to a thing, but is not part of its essence [Aristotle] |
12290 | Destruction is dissolution of essence [Aristotle] |
12286 | If two things are the same, they must have the same source and origin [Aristotle] |
12266 | 'Same' is mainly for names or definitions, but also for propria, and for accidents [Aristotle] |
12287 | Two identical things have the same accidents, they are the same; if the accidents differ, they're different [Aristotle] |
12288 | Numerical sameness and generic sameness are not the same [Aristotle] |
12259 | Reasoning is when some results follow necessarily from certain claims [Aristotle] |
18960 | Most predictions are uninteresting, and are only sought in order to confirm a theory [Putnam] |
12271 | Induction is the progress from particulars to universals [Aristotle] |
12293 | We say 'so in cases of this kind', but how do you decide what is 'of this kind'? [Aristotle] |
12277 | Friendship is preferable to money, since its excess is preferable [Aristotle] |
12276 | Justice and self-control are better than courage, because they are always useful [Aristotle] |
12275 | We value friendship just for its own sake [Aristotle] |
12281 | Man is intrinsically a civilized animal [Aristotle] |
12265 | All water is the same, because of a certain similarity [Aristotle] |
12278 | 'Being' and 'oneness' are predicated of everything which exists [Aristotle] |