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7807
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The laws of thought are true, but they are not the axioms of logic [Bolzano, by George/Van Evra]
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Full Idea:
Bolzano said the 'laws of thought' (identity, contradiction, excluded middle) are true, but nothing of interest follows from them. Logic obeys them, but they are not logic's first principles or axioms.
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From:
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837], §3) by George / Van Evra - The Rise of Modern Logic
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A reaction:
An interesting and crucial distinction. For samples of proposed axioms of logic, see Ideas 6408, 7798 and 7797.
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9618
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Bolzano wanted to reduce all of geometry to arithmetic [Bolzano, by Brown,JR]
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Full Idea:
Bolzano if the father of 'arithmetization', which sought to found all of analysis on the concepts of arithmetic and to eliminate geometrical notions entirely (with logicism taking it a step further, by reducing arithmetic to logic).
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From:
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837]) by James Robert Brown - Philosophy of Mathematics Ch. 3
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A reaction:
Brown's book is a defence of geometrical diagrams against Bolzano's approach. Bolzano sounds like the modern heir of Pythagoras, if he thinks that space is essentially numerical.
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9830
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Bolzano began the elimination of intuition, by proving something which seemed obvious [Bolzano, by Dummett]
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Full Idea:
Bolzano began the process of eliminating intuition from analysis, by proving something apparently obvious (that as continuous function must be zero at some point). Proof reveals on what a theorem rests, and that it is not intuition.
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From:
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837]) by Michael Dummett - Frege philosophy of mathematics Ch.6
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A reaction:
Kant was the target of Bolzano's attack. Two responses might be to say that many other basic ideas are intuited but impossible to prove, or to say that proof itself depends on intuition, if you dig deep enough.
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17265
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Philosophical proofs in mathematics establish truths, and also show their grounds [Bolzano, by Correia/Schnieder]
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Full Idea:
Mathematical proofs are philosophical in method if they do not only demonstrate that a certain mathematical truth holds but if they also disclose why it holds, that is, if they uncover its grounds.
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From:
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837]) by Correia,F/Schnieder,B - Grounding: an opinionated introduction 2.3
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A reaction:
I aim to defend the role of explanation in mathematics, but this says that this is only if the proofs are 'philosophical', which may be of no interest to mathematicians. Oh well, that's their loss.
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23708
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Humeans see properties as having no more essential features and relations than their distinctness [Friend/Kimpton-Nye, by PG]
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Full Idea:
The Humean view says properties are 'quiddities', which individuates properties by nothing more than their distinctness from one another, so that dispositions are not essential to them, and there is no limit to possible property recombination.
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From:
report of Friend/Kimpton-Nye (Dispositions and Powers [2023], 3.3.1) by PG - Db (ideas)
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A reaction:
[my summary] All of this is implied by Hume, rather than stated. David Lewis supports this view. The theory of basic powers is the view's main opponent. This quidditist view is not found in physics, where a property's modal profile matters.
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23709
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Dispositions are what individuate properties, and they constitute their essence [Friend/Kimpton-Nye]
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Full Idea:
Dispositions constitute the essences of properties, and hence the identity of a property is not primitive ('quidditism'), but is given in terms of its dispositional relations to other properties.
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From:
Friend/Kimpton-Nye (Dispositions and Powers [2023], 3.3.1)
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A reaction:
I like the picture that powers are basic, giving rise to dispositions, which combine to produce qualitative and active properties. Powers are precise and relatively few, and properties are ill-defined and very numerous. Being 'influential', for example.
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23714
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Dispositional essentialism (unlike the grounding view) says only fundamental properties are powers [Friend/Kimpton-Nye]
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Full Idea:
Dispositional essentialism yields the view that just fundamental properties and some evolved macro properties are powers. The grounding view, by contrast, seems to yield the result that all properties are powers.
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From:
Friend/Kimpton-Nye (Dispositions and Powers [2023], 3.7)
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A reaction:
For the second view, Mumford (for example) claims that the sphericity of a ball is a power, but that seems to miss the whole motivation for the powers ontology, which offers a fairly fundamental explanation of laws and modality.
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23704
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We could analyse dispositions as 'possibilities', with no mention of a stimulus [Friend/Kimpton-Nye]
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Full Idea:
We might abandon the relational analysis of dispositions (as stimulus-effect), and just say a disposition is a 'possibility', which simply can manifest, however that manifestation comes about.
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From:
Friend/Kimpton-Nye (Dispositions and Powers [2023], 2.3.5)
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A reaction:
[Compressed. He particularly cites Barbara Vetter] A mere 'possibility' seems to cover passive states as well as potentially active ones. A cushion can be dented, but I wouldn't say it was 'disposed' to dent. Radioactive decay is a disposition, though.
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9185
|
Bolzano wanted to avoid Kantian intuitions, and prove everything that could be proved [Bolzano, by Dummett]
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Full Idea:
Bolzano was determined to expel Kantian intuition from analysis, and to prove from first principles anything that could be proved, no matter how obvious it might seem when thought of in geometrical terms.
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From:
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837]) by Michael Dummett - The Philosophy of Mathematics 2.3
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A reaction:
This is characteristic of the Enlightenment Project, well after the Enlightenment. It is a step towards Frege's attack on 'psychologism' in mathematics. The problem is that it led us into a spurious platonism. We live in troubled times.
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17264
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Propositions are abstract structures of concepts, ready for judgement or assertion [Bolzano, by Correia/Schnieder]
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Full Idea:
Bolzano conceived of propositions as abstract objects which are structured compounds of concepts and potential contents of judgements and assertions.
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From:
report of Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837]) by Correia,F/Schnieder,B - Grounding: an opinionated introduction 2.3
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A reaction:
Personally I think of propositions as brain events, the constituents of thought about the world, but that needn't contradict the view of them as 'abstract'.
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12232
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A 'proposition' is the sense of a linguistic expression, and can be true or false [Bolzano]
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Full Idea:
What I mean by 'propositions' is not what the grammarians call a proposition, namely the linguistic expression, but the mere sense of this expression, is what is meant by proposition in itself or object proposition. This sense can be true or false.
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From:
Bernard Bolzano (Theory of Science (Wissenschaftslehre, 4 vols) [1837], Pref?)
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A reaction:
This seems to be the origin of what we understand by 'proposition'. The disputes are over whether such things exists, and whether they are features of minds or features of the world (resembling facts).
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7667
|
There are two sides to men - the pleasantly social, and the violent and creative [Diderot, by Berlin]
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Full Idea:
Diderot is among the first to preach that there are two men: the artificial man, who belongs in society and seeks to please, and the violent, bold, criminal instinct of a man who wishes to break out (and, if controlled, is responsible for works of genius.
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From:
report of Denis Diderot (works [1769], Ch.3) by Isaiah Berlin - The Roots of Romanticism
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A reaction:
This has an obvious ancestor in Plato's picture (esp. in 'Phaedrus') of the two conflicting sides to the psuché, which seem to be reason and emotion. In Diderot, though, the suppressed man has virtues, which Plato would deny.
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