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All the ideas for 'Reply to Professor Marcus', 'Models' and 'Occasions of Identity'

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12 ideas

5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
Either reference really matters, or we don't need to replace it with substitutions [Quine]
     Full Idea: When we reconstrue quantification in terms of substituted expressions rather than real values, we waive reference. ...but if reference matters, we cannot afford to waive it as a category; and if it does not, we do not need to.
     From: Willard Quine (Reply to Professor Marcus [1962], p.183)
     A reaction: An odd dilemma to pose. Presumably the substitution account is an attempt to explain how language actually works, without mentioning dubious direct ontological commitment in the quantifiers.
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
A CAR and its major PART can become identical, yet seem to have different properties [Gallois]
     Full Idea: At t1 there is a whole CAR, and a PART of it, which is everything except the right front wheel. At t2 the wheel is removed, leaving just PART, so that CAR is now PART. But PART was a proper part of CAR, and CAR had the front wheel. Different properties!
     From: André Gallois (Occasions of Identity [1998], 1.II)
     A reaction: [compressed summary] The problem is generated by appealing to Leibniz's Law. My immediate reaction is that this is the sort of trouble you get into if you include such temporal truths about things as 'properties'.
9. Objects / E. Objects over Time / 1. Objects over Time
Gallois hoped to clarify identity through time, but seems to make talk of it impossible [Hawley on Gallois]
     Full Idea: A problem for Gallois is that he leaves us no way to talk about questions of genuine identity through time, and thus undercuts one motivation for his own position.
     From: comment on André Gallois (Occasions of Identity [1998]) by Katherine Hawley - How Things Persist 5.8
     A reaction: Gallois seems to need a second theory of identity to support his Occasional Identity theory. Two things need an identity each, before we can say that the two identities coincide. (Time to read Gallois!)
9. Objects / F. Identity among Objects / 3. Relative Identity
Gallois is committed to identity with respect to times, and denial of simple identity [Gallois, by Sider]
     Full Idea: Gallois's core claim is that the identity relation holds with respect to times, ...and he must claim that there is no such thing as the relation of identity simpliciter.
     From: report of André Gallois (Occasions of Identity [1998]) by Theodore Sider - Four Dimensionalism 5.5
     A reaction: Gallois is essentially responding to the statue and clay problem, but it seems a bit drastic to entirely change our concept of two things being identical, such as Hesperus and Phosphorus. 'Identity' seems to have several meanings; let's sort them out.
9. Objects / F. Identity among Objects / 6. Identity between Objects
Occasional Identity: two objects can be identical at one time, and different at others [Gallois, by Hawley]
     Full Idea: Gallois' Occasional Identity Thesis is that objects can be identical at one time without being identical at all times.
     From: report of André Gallois (Occasions of Identity [1998]) by Katherine Hawley - How Things Persist 5.4
     A reaction: The analogy is presumably with two crossing roads being identical at one place but not at others. It is a major misunderstanding to infer from Special Relativity that time is just like space.
14. Science / B. Scientific Theories / 7. Scientific Models
Theoretical models can represent, by mapping onto the data-models [Portides]
     Full Idea: The semantic approach contends that theoretical models ...are candidates for representing physical systems by virtue of the fact that they stand in mapping relations to corresponding data-models.
     From: Demetris Portides (Models [2008], 'Current')
     A reaction: Sounds like a neat and satisfying picture.
In the 'received view' models are formal; the 'semantic view' emphasises representation [Portides, by PG]
     Full Idea: The 'received view' of models is that they are Tarskian formal axiomatic calculi interpreted by meta-mathematical models. The 'semantic' view of models gives equal importance to their representational capacity.
     From: report of Demetris Portides (Models [2008], 'background') by PG - Db (ideas)
     A reaction: The Tarskian view is the one covered in my section on Model Theory. Portides favours the semantic account, and I am with him all the way. Should models primarily integrate with formal systems, or with the world? Your choice...
Representational success in models depends on success of their explanations [Portides]
     Full Idea: Models are representational, independently of the strength of their relation to theory, depending on how well they achieve the purpose of providing explanations for what occurs in physical systems.
     From: Demetris Portides (Models [2008], 'Current')
     A reaction: This doesn't sound quite right. It seems possible to have a perfect representation of a system which remains quite baffling (because too complex, or with obscure ingredients). Does the stylised London tube map explain well but represent badly?
The best model of the atomic nucleus is the one which explains the most results [Portides]
     Full Idea: The unified model can be considered a better representation of the atomic nucleus in comparison to the liquid-drop and shell models, because it explains most of the known results about the nucleus.
     From: Demetris Portides (Models [2008], 'Current')
     A reaction: The point here is that models are evaluated not just by their accuracy, but by their explanatory power. Presumably a great model is satisfying and illuminating. Do the best models capture the essence of a thing?
'Model' belongs in a family of concepts, with representation, idealisation and abstraction [Portides]
     Full Idea: A better understanding of 'model', as used in science, could be achieved if we examine it as a member of the triad of concepts of representation, idealisation and abstraction.
     From: Demetris Portides (Models [2008], 'Intro')
     A reaction: Abstraction seems to have a bad name in philosophy, and yet when you come to discuss things like models, you can't express it any other way.
Models are theory-driven, or phenomenological (more empirical and specific) [Portides]
     Full Idea: 'Theory-driven' models are constructed in a systematic theory-regulated way by supplementing the theoretical calculus with locally operative hypotheses. 'Phenomenological' models deploy semi-empirical results, with ad hoc hypotheses, and extra concepts.
     From: Demetris Portides (Models [2008], 'Intro')
     A reaction: [compressed] I am not at all clear about this distinction, even after reading his whole article. The first type of model seems more general, while the second seems tuned to particular circumstances. He claims the second type is more explanatory.
14. Science / D. Explanation / 2. Types of Explanation / i. Explanations by mechanism
General theories may be too abstract to actually explain the mechanisms [Portides]
     Full Idea: If theoretical models are highly abstract and idealised descriptions of phenomena, they may only represent general features, and fail to explain the specific mechanisms at work in physical systems.
     From: Demetris Portides (Models [2008], 'Current')
     A reaction: [compressed] While there may be an ideal theory that explains everything, it sounds right capturing the actual mechanism (such as the stirrup bone in the ear) is not at all theoretical.