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All the ideas for 'Katzav on limitations of dispositions', 'Bayesianism' and 'Investigations into Logical Deduction'

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8 ideas

5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking]
     Full Idea: Gentzen thought that his natural deduction gets at the heart of logical reasoning, and used the sequent calculus only as a convenient tool for proving his chief results.
     From: report of Gerhard Gentzen (Investigations into Logical Deduction [1935]) by Ian Hacking - What is Logic? §05
14. Science / C. Induction / 6. Bayes's Theorem
Probability of H, given evidence E, is prob(H) x prob(E given H) / prob(E) [Horwich]
     Full Idea: Bayesianism says ideally rational people should have degrees of belief (not all-or-nothing beliefs), corresponding with probability theory. Probability of H, given evidence E, is prob(H) X prob(E given H) / prob(E).
     From: Paul Horwich (Bayesianism [1992], p.41)
Bayes' theorem explains why very surprising predictions have a higher value as evidence [Horwich]
     Full Idea: Bayesianism can explain the fact that in science surprising predictions have greater evidential value, as the equation produces a higher degree of confirmation.
     From: Paul Horwich (Bayesianism [1992], p.42)
26. Natural Theory / B. Natural Kinds / 1. Natural Kinds
The natural kinds are objects, processes and properties/relations [Ellis]
     Full Idea: There are three hierarchies of natural kinds: objects or substances (substantive universals), events or processes (dynamic universals), and properties or relations (tropic universals).
     From: Brian Ellis (Katzav on limitations of dispositions [2005], 91)
     A reaction: Most interesting here is the identifying of natural kinds with universals, making universals into the families of nature. Universals are high-level sets of natural kinds. To grasp universals you must see patterns, and infer the underlying order.
26. Natural Theory / D. Laws of Nature / 2. Types of Laws
Least action is not a causal law, but a 'global law', describing a global essence [Ellis]
     Full Idea: The principle of least action is not a causal law, but is what I call a 'global law', which describes the essence of the global kind, which every object in the universe necessarily instantiates.
     From: Brian Ellis (Katzav on limitations of dispositions [2005])
     A reaction: As a fan of essentialism I find this persuasive. If I inherit part of my essence from being a mammal, I inherit other parts of my essence from being an object, and all objects would share that essence, so it would look like a 'law' for all objects.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
A species requires a genus, and its essence includes the essence of the genus [Ellis]
     Full Idea: A specific universal can exist only if the generic universal of which it is a species exists, but generic universals don't depend on species; …the essence of any genus is included in its species, but not conversely.
     From: Brian Ellis (Katzav on limitations of dispositions [2005], 91)
     A reaction: Thus the species 'electron' would be part of the genus 'lepton', or 'human' part of 'mammal'. The point of all this is to show how individual items connect up with the rest of the universe, giving rise to universal laws, such as Least Action.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / c. Essence and laws
A hierarchy of natural kinds is elaborate ontology, but needed to explain natural laws [Ellis]
     Full Idea: The hierarchy of natural kinds proposed by essentialism may be more elaborate than is strictly required for purposes of ontology, but it is necessary to explain the necessity of the laws of nature, and the universal applicability of global principles.
     From: Brian Ellis (Katzav on limitations of dispositions [2005], 91)
     A reaction: I am all in favour of elaborating ontology in the name of best explanation. There seem, though, to be some remaining ontological questions at the point where the explanations of essentialism run out.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / d. Knowing essences
Without general principles, we couldn't predict the behaviour of dispositional properties [Ellis]
     Full Idea: It is objected to dispositionalism that without the principle of least action, or some general principle of equal power, the specific dispositional properties of things could tell us very little about how these things would be disposed to behave.
     From: Brian Ellis (Katzav on limitations of dispositions [2005], 90)
     A reaction: Ellis attempts to meet this criticism, by placing dispositional properties within a hierarchy of broader properties. There remains a nagging doubt about how essentialism can account for space, time, order, and the existence of essences.