Combining Texts

All the ideas for 'Natural Kinds and Biological Realism', 'The Logic of Boundaryless Concepts' and 'Symbolic Logic (with Langford)'

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6 ideas

5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
9390 Logic guides thinking, but it isn't a substitute for it [Rumfitt]
     Full Idea: Logic is part of a normative theory of thinking, not a substitute for thinking.
     From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.13)
     A reaction: There is some sort of logicians' dream, going back to Leibniz, of a reasoning engine, which accepts propositions and outputs inferences. I agree with this idea. People who excel at logic are often, it seems to me, modest at philosophy.
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
9389 Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt]
     Full Idea: Vagueness in respect of membership is consistency with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of a concept.
     From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5)
     A reaction: I find this view of sets much more appealing than the one that identifies a set with its members. The empty set is less of a problem, as well as non-existents. Logicians prefer the extensional view because it is tidy.
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
7803 Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle]
     Full Idea: C.I.Lewis began his groundbreaking work in modal logic because he was concerned about the unreliability of the material conditional as a translation of 'If ... then' conditionals.
     From: report of C.I. Lewis (Symbolic Logic (with Langford) [1932]) by Rod Girle - Modal Logics and Philosophy 12.3
     A reaction: Compare 'if this is square then it has four corners' with 'if it rains then our afternoon is ruined'. Different modalities seem to be involved. We even find that 'a square has four corners' will be materially implied if it rains!
26. Natural Theory / B. Natural Kinds / 1. Natural Kinds
17371 Some kinds are very explanatory, but others less so, and some not at all [Devitt]
     Full Idea: Explanatory significance, hence naturalness, comes in degrees: positing some kinds may be very explanatory, positing others, only a little bit explanatory, positing others still, not explanatory at all.
     From: Michael Devitt (Natural Kinds and Biological Realism [2009], 4)
     A reaction: He mentions 'cousin' as a natural kind that is not very explanatory of anything. It interests us as humans, but not at all in other animals, it seems. ...Nice thought, though, that two squirrels might be cousins...
27. Natural Reality / G. Biology / 5. Species
17372 The higher categories are not natural kinds, so the Linnaean hierarchy should be given up [Devitt]
     Full Idea: The signs are that the higher categories are not natural kinds and so the Linnaean hierarchy must be abandoned. ...This is not abandoning a hierarchy altogether, it is not abandoning a tree of life.
     From: Michael Devitt (Natural Kinds and Biological Realism [2009], 6)
     A reaction: Devitt's underlying point is that the higher and more general kinds do not have an essence (a specific nature), which is the qualification to be a natural kind. They explain nothing. Essence is the hallmark of natural kinds. Hmmm.
17373 Species pluralism says there are several good accounts of what a species is [Devitt]
     Full Idea: Species pluralism is the view that there are several equally good accounts of what it is to be a species.
     From: Michael Devitt (Natural Kinds and Biological Realism [2009], 7)
     A reaction: Devitt votes for it, and cites Dupré, among many other. Given the existence of rival accounts, all making good points, it is hard to resist this view.