Combining Philosophers

All the ideas for Oswald Veblen, Graeme Forbes and Edwin D. Mares

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60 ideas

1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
There must be a plausible epistemological theory alongside any metaphysical theory [Forbes,G]
     Full Idea: No metaphysical account which renders it impossible to give a plausible epistemological theory is to be countenanced.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 9.1)
     A reaction: It is hard to object to this principle, though we certainly don't want to go verificationist, and thus rule out speculations about metaphysics which are beyond any possible knowledge. Some have tried to prove that something must exist (e.g. Jacquette).
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
After 1903, Husserl avoids metaphysical commitments [Mares]
     Full Idea: In Husserl's philosophy after 1903, he is unwilling to commit himself to any specific metaphysical views.
     From: Edwin D. Mares (A Priori [2011], 08.2)
2. Reason / A. Nature of Reason / 9. Limits of Reason
Inconsistency doesn't prevent us reasoning about some system [Mares]
     Full Idea: We are able to reason about inconsistent beliefs, stories, and theories in useful and important ways
     From: Edwin D. Mares (Negation [2014], 1)
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / a. Symbols of PL
The symbol 'ι' forms definite descriptions; (ιx)F(x) says 'the x which is such that F(x)' [Forbes,G]
     Full Idea: We use the symbol 'ι' (Greek 'iota') to form definite descriptions, reading (ιx)F(x) as 'the x which is such that F(x)', or simply as 'the F'.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.1)
     A reaction: Compare the lambda operator in modal logic, which picks out predicates from similar formulae.
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Intuitionism as natural deduction has no rule for negation [Mares]
     Full Idea: In intuitionist logic each connective has one introduction and one elimination rule attached to it, but in the classical system we have to add an extra rule for negation.
     From: Edwin D. Mares (Negation [2014], 5.5)
     A reaction: How very intriguing. Mares says there are other ways to achieve classical logic, but they all seem rather cumbersome.
Intuitionist logic looks best as natural deduction [Mares]
     Full Idea: Intuitionist logic appears most attractive in the form of a natural deduction system.
     From: Edwin D. Mares (Negation [2014], 5.5)
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
Three-valued logic is useful for a theory of presupposition [Mares]
     Full Idea: One reason for wanting a three-valued logic is to act as a basis of a theory of presupposition.
     From: Edwin D. Mares (Negation [2014], 3.1)
     A reaction: [He cites Strawson 1950] The point is that you can get a result when the presupposition does not apply, as in talk of the 'present King of France'.
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
We have no adequate logic at the moment, so mathematicians must create one [Veblen]
     Full Idea: Formal logic has to be taken over by mathematicians. The fact is that there does not exist an adequate logic at the present time, and unless the mathematicians create one, no one else is likely to do so.
     From: Oswald Veblen (Presidential Address of Am. Math. Soc [1924], 141), quoted by Stewart Shapiro - Philosophy of Mathematics
     A reaction: This remark was made well after Frege, but before the advent of Gödel and Tarski. That implies that he was really thinking of meta-logic.
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Material implication (and classical logic) considers nothing but truth values for implications [Mares]
     Full Idea: The problem with material implication, and classical logic more generally, is that it considers only the truth value of formulas in deciding whether to make an implication stand between them. It ignores everything else.
     From: Edwin D. Mares (Negation [2014], 7.1)
     A reaction: The obvious problem case is conditionals, and relevance is an obvious extra principle that comes to mind.
In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares]
     Full Idea: Among the virtues of classical logic is the fact that the connectives are related to one another in elegant ways that often involved negation. For example, De Morgan's Laws, which involve negation, disjunction and conjunction.
     From: Edwin D. Mares (Negation [2014], 2.2)
     A reaction: Mares says these enable us to take disjunction or conjunction as primitive, and then define one in terms of the other, using negation as the tool.
5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence
Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares]
     Full Idea: On its standard reading, excluded middle tells us that bivalence holds. To reject excluded middle, we must reject either non-contradiction, or ¬(A∧B) ↔ (¬A∨¬B) [De Morgan 3], or the principle of double negation. All have been tried.
     From: Edwin D. Mares (Negation [2014], 2.2)
Standard disjunction and negation force us to accept the principle of bivalence [Mares]
     Full Idea: If we treat disjunction in the standard way and take the negation of a statement A to mean that A is false, accepting excluded middle forces us also to accept the principle of bivalence, which is the dictum that every statement is either true or false.
     From: Edwin D. Mares (Negation [2014], 1)
     A reaction: Mates's point is to show that passively taking the normal account of negation for granted has important implications.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
The connectives are studied either through model theory or through proof theory [Mares]
     Full Idea: In studying the logical connectives, philosophers of logic typically adopt the perspective of either model theory (givng truth conditions of various parts of the language), or of proof theory (where use in a proof system gives the connective's meaning).
     From: Edwin D. Mares (Negation [2014], 1)
     A reaction: [compressed] The commonest proof theory is natural deduction, giving rules for introduction and elimination. Mates suggests moving between the two views is illuminating.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and
Is the meaning of 'and' given by its truth table, or by its introduction and elimination rules? [Forbes,G]
     Full Idea: The typical semantic account of validity for propositional connectives like 'and' presupposes that meaning is given by truth-tables. On the natural deduction view, the meaning of 'and' is given by its introduction and elimination rules.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.4)
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
Many-valued logics lack a natural deduction system [Mares]
     Full Idea: Many-valued logics do not have reasonable natural deduction systems.
     From: Edwin D. Mares (Negation [2014], 1)
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
Situation semantics for logics: not possible worlds, but information in situations [Mares]
     Full Idea: Situation semantics for logics consider not what is true in worlds, but what information is contained in situations.
     From: Edwin D. Mares (Negation [2014], 6.2)
     A reaction: Since many theoretical physicists seem to think that 'information' might be the most basic concept of a natural ontology, this proposal is obviously rather appealing. Barwise and Perry are the authors of the theory.
5. Theory of Logic / K. Features of Logics / 2. Consistency
Consistency is semantic, but non-contradiction is syntactic [Mares]
     Full Idea: The difference between the principle of consistency and the principle of non-contradiction is that the former must be stated in a semantic metalanguage, whereas the latter is a thesis of logical systems.
     From: Edwin D. Mares (Negation [2014], 2.2)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
The truth of the axioms doesn't matter for pure mathematics, but it does for applied [Mares]
     Full Idea: The epistemological burden of showing that the axioms are true is removed if we are only studying pure mathematics. If, however, we want to look at applied mathematics, then this burden returns.
     From: Edwin D. Mares (A Priori [2011], 11.4)
     A reaction: One of those really simple ideas that hits the spot. Nice. The most advanced applied mathematics must rest on counting and measuring.
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Mathematics is relations between properties we abstract from experience [Mares]
     Full Idea: Aristotelians treat mathematical facts as relations between properties. These properties, moreover, are abstracted from our experience of things. ...This view finds a natural companion in structuralism.
     From: Edwin D. Mares (A Priori [2011], 11.7)
     A reaction: This is the view of mathematics that I personally favour. The view that we abstract 'five' from a group of five pebbles is too simplistic, but this is the right general approach.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares]
     Full Idea: For the intuitionist, talk of mathematical objects is rather misleading. For them, there really isn't anything that we should call the natural numbers, but instead there is counting. What intuitionists study are processes, such as counting and collecting.
     From: Edwin D. Mares (Negation [2014], 5.1)
     A reaction: That is the first time I have seen mathematical intuitionism described in a way that made it seem attractive. One might compare it to a metaphysics based on processes. Apparently intuitionists struggle with infinite sets and real numbers.
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
Vagueness problems arise from applying sharp semantics to vague languages [Forbes,G]
     Full Idea: It is very plausible that the sorites paradoxes arose from the application of a semantic apparatus appropriate only for sharp predicates to languages containing vague predicates (rather than from deficiency of meaning, or from incoherence).
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.3)
     A reaction: Sounds wrong. Of course, logic has been designed for sharp predicates, and natural languages are awash with vagueness. But the problems of vagueness bothered lawyers long before logicians like Russell began to worry about it.
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
In all instances of identity, there must be some facts to ensure the identity [Forbes,G]
     Full Idea: For each instance of identity or failure of identity, there must be facts in virtue of which that instance obtains. ..Enough has been said to lend this doctrine some plausibility.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.5)
     A reaction: Penelope Mackie picks this out from Forbes as a key principle. It sounds to be in danger of circularity, unless the 'facts' can be cited without referring to, or implicitly making use of, identities - which seems unlikely.
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
If we combined two clocks, it seems that two clocks may have become one clock. [Forbes,G]
     Full Idea: If we imagine a possible world in which two clocks in a room make one clock from half the parts of each, the judgement 'these two actual clocks could have been a single clock' does not seem wholly false.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.4)
     A reaction: You would, of course, have sufficient parts left over to make a second clock, so they look like a destroyed clock, so I don't think I find Forbes's intuition on this one very persuasive.
9. Objects / D. Essence of Objects / 3. Individual Essences
Only individual essences will ground identities across worlds in other properties [Forbes,G, by Mackie,P]
     Full Idea: Forbes argues that, unless we posit individual essences, we cannot guarantee that identities across possible worlds will be appropriately grounded in other properties.
     From: report of Graeme Forbes (The Metaphysics of Modality [1985]) by Penelope Mackie - How Things Might Have Been 2.4
     A reaction: There is a confrontation between Wiggins, who says identity is primitive, and Forbes, who says identity must be grounded in other properties. I think I side with Forbes.
An individual essence is a set of essential properties which only that object can have [Forbes,G]
     Full Idea: An individual essence of an object x is a set of properties I which satisfies the following conditions: i. every property P in I is an essential property of x; ii. it is not possible that some object y distinct from x has every member of I.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: I am coming to the view that stable natural kinds (like electrons or gold) do not have individual essences, but complex kinds (like tigers or tables) do. The view is based on the idea that explanatory power is what individuates an essence.
Non-trivial individual essence is properties other than de dicto, or universal, or relational [Forbes,G]
     Full Idea: A non-trivial individual essence is properties other than a) those following from a de dicto truth, b) properties of existence and self-identity (or their cognates), c) properties derived from necessities in some other category.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: [I have compressed Forbes] Rather than adding all these qualificational clauses to our concept, we could just tighten up on the notion of a property, saying it is something which is causally efficacious, and hence explanatory.
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essential properties depend on a category, and perhaps also on particular facts [Forbes,G]
     Full Idea: The essential properties of a thing will typically depend upon what category of thing it is, and perhaps also on some more particular facts about the thing itself.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: I see no way of dispensing with the second requirement, in the cases of complex entities like animals. If all samples are the same, then of course we can define a sample's essence through its kind, but not if samples differ in any way.
9. Objects / D. Essence of Objects / 6. Essence as Unifier
A property is essential iff the object would not exist if it lacked that property [Forbes,G]
     Full Idea: A property P is an essential property of an object x iff x could not exist and lack P, that is, as they say, iff x has P at every world at which x exists.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 1)
     A reaction: This immediately places the existence of x outside the normal range of its properties, so presumably 'existence is not a predicate', but that dictum may be doubted. As it stands this definition will include trivial and vacuous properties.
Properties are trivially essential if they are not grounded in a thing's specific nature [Forbes,G]
     Full Idea: Essential properties may be trivial or nontrivial. It is characteristic of P's being trivially essential to x that x's possession of P is not grounded in the specific nature of x.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2)
     A reaction: This is where my objection to the modal view of essence arises. How is he going to explain 'grounded' and 'specific nature' without supplying an entirely different account of essence?
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
Essential properties are those without which an object could not exist [Forbes,G]
     Full Idea: An essential property of an object x is a property without possessing which x could not exist.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: This is certainly open to question. See Joan Kung's account of Aristotle on essence. I am necessarily more than eight years old (now), and couldn't exist without that property, but is the property part of my essence?
A relation is essential to two items if it holds in every world where they exist [Forbes,G]
     Full Idea: A relation R is essential to x and y (in that order) iff Rxy holds at every world where x and y both exist.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2)
     A reaction: I find this bizarre. Not only does this seem to me to have nothing whatever to do with essence, but also the relation might hold even though it is a purely contingent matter. All rabbits are a reasonable distance from the local star. Essence of rabbit?
9. Objects / D. Essence of Objects / 7. Essence and Necessity / c. Essentials are necessary
Trivially essential properties are existence, self-identity, and de dicto necessities [Forbes,G]
     Full Idea: The main groups of trivially essential properties are (a) existence, self-identity, or their consequences in S5; and (b) properties possessed in virtue of some de dicto necessary truth.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2)
     A reaction: He adds 'extraneously essential' properties, which also strike me as being trivial, involving relations. 'Is such that 2+2=4' or 'is such that something exists' might be necessary, but they don't, I would say, have anything to do with essence.
9. Objects / D. Essence of Objects / 9. Essence and Properties
A property is 'extraneously essential' if it is had only because of the properties of other objects [Forbes,G]
     Full Idea: P is 'extraneously essential' to x iff it is possessed by x at any world w only in virtue of the possession at w of certain properties by other objects.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2)
     A reaction: I would say that these are the sorts of properties which have nothing to do with being essential, even if they are deemed to be necessary.
9. Objects / D. Essence of Objects / 11. Essence of Artefacts
Artefacts have fuzzy essences [Forbes,G]
     Full Idea: Artefacts can be ascribed fuzzy essences. ...We might say that it is essential to an artefact to have 'most' of its parts.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.6)
     A reaction: I think I prefer to accept the idea that essences are unstable things, in all cases. For all we know, electrons might subtly change their general character, or cease to be uniform, tomorrow. Essences explain, and what needs explaining changes.
Same parts does not ensure same artefact, if those parts could constitute a different artefact [Forbes,G]
     Full Idea: Sameness of parts is not sufficient for identity of artefacts at a world, since the very same parts may turn up at different times as the parts of artefacts with different designs and functions.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.2)
     A reaction: Thus the Ship of Theseus could be dismantled and turned into a barn (as happened with the 'Mayflower'). They could then be reconstituted as the ship, which would then have two beginnings (as Chris Hughes has pointed out).
One might be essentialist about the original bronze from which a statue was made [Forbes,G]
     Full Idea: In the case of artefacts, there is an essentialism about original matter; for instance, it would be said of any particular bronze statue that it could not have been cast from a totally different quantity of bronze.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 3)
     A reaction: Forbes isn't endorsing this, and it doesn't sound convincing. He quotes the thought 'I wish I had made this pot from a different piece of clay'. We might corrupt a statue by switching bronze, but I don't think the sculptor could do so.
9. Objects / E. Objects over Time / 12. Origin as Essential
An individual might change their sex in a world, but couldn't have differed in sex at origin [Forbes,G]
     Full Idea: In the time of a single world, the same individual can undergo a change of sex, but it is less clear that an individual of one sex could have been, from the outset, an individual of another.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 6.5)
     A reaction: I don't find this support for essentiality of origin very persuasive. I struggle with these ideas. Given my sex yesterday, then presumably I couldn't have had a different sex yesterday. Given that pigs can fly, pigs can fly. What am I missing?
9. Objects / F. Identity among Objects / 1. Concept of Identity
Identities must hold because of other facts, which must be instrinsic [Forbes,G, by Mackie,P]
     Full Idea: Forbes has two principles of identity, which we can call the No Bare Identities Principle (identities hold in virtue of other facts), and the No Extrinsic Determination Principle (that only intrinsic facts of a thing establish identity).
     From: report of Graeme Forbes (The Metaphysics of Modality [1985], 127-8) by Penelope Mackie - How Things Might Have Been 2.7
     A reaction: The job of the philosopher is to prise apart the real identities of things from the way in which we conceive of identities. I take these principles to apply to real identities, not conceptual identities.
10. Modality / A. Necessity / 4. De re / De dicto modality
De re modal formulae, unlike de dicto, are sensitive to transworld identities [Forbes,G]
     Full Idea: The difference between de re and de dicto formulae is a difference between formulae which are, and formulae which are not, sensitive to the identities of objects at various worlds.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 3.1)
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
De re necessity is a form of conceptual necessity, just as de dicto necessity is [Forbes,G]
     Full Idea: De re necessity does not differ from de dicto necessity in respect of how it arises: it is still a form of conceptual necessity.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 9.4)
     A reaction: [Forbes proceeds to argue for this claim] Forbes defends a form of essentialism, but takes the necessity to arise from a posteriori truths because of the a priori involvement of other concepts (rather as Kripke argues).
The source of de dicto necessity is not concepts, but the actual properties of the thing [Forbes,G]
     Full Idea: It is widely held that the source of de dicto necessity is in concepts, ..but I deny this... even with simple de dicto necessities, the source of the necessity is to be found in the properties to which the predicates of the de dicto truth refer.
     From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 3)
     A reaction: It is normal nowadays to say this about de re necessities, but this is more unusual.
10. Modality / D. Knowledge of Modality / 2. A Priori Contingent
Light in straight lines is contingent a priori; stipulated as straight, because they happen to be so [Mares]
     Full Idea: It seems natural to claim that light rays moving in straight lines is contingent but a priori. Scientists stipulate that they are the standard by which we measure straightness, but their appropriateness for this task is a contingent feature of the world.
     From: Edwin D. Mares (A Priori [2011], 02.9)
     A reaction: This resembles the metre rule in Paris. It is contingent that something is a certain way, so we make being that way a conventional truth, which can therefore be known via the convention, rather than via the contingent fact.
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
Unlike places and times, we cannot separate possible worlds from what is true at them [Forbes,G]
     Full Idea: There is no means by which we might distinguish a possible world from what is true at it. ...Whereas our ability to separate a place, or a time, from its occupier is crucial to realism about places and times, as is a distance relation.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.2)
     A reaction: He is objecting to Lewis's modal realism. I'm not fully convinced. It depends whether we are discussing real ontology or conceptual space. In the latter I see no difference between times and possible worlds. In ontology, a 'time' is weird.
The problem with possible worlds realism is epistemological; we can't know properties of possible objects [Forbes,G]
     Full Idea: The main objection to realism about worlds is from epistemology. Knowledge of properties of objects requires experience of these objects, which must be within the range of our sensory faculties, but only concrete actual objects achieve that.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.2)
     A reaction: This pinpoints my dislike of the whole possible worlds framework, ontologically speaking. I seem to be an actualist. I take possibilities to be inferences to the best explanation from the powers we know of in the actual world. We experience potentiality.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Possible worlds are points of logical space, rather like other times than our own [Forbes,G]
     Full Idea: Someone impressed by the parallel between tense and modal operators ...might suggest that just as we can speak of places and times forming their own manifolds or spaces, so we can say that worlds are the points of logical space.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.2)
     A reaction: I particularly like the notion of worlds being "points of logical space", and am inclined to remove it from this context and embrace it as the correct way to understand possible worlds. We must understand logical or conceptual space.
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Transworld identity concerns the limits of possibility for ordinary things [Forbes,G]
     Full Idea: An elucidation of transworld identity can be regarded as an elucidation of the boundaries of possibility for ordinary things.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: I presume that if we don't search for some such criterion, we just have to face the possibility that Aristotle could have been a poached egg in some possible world. To know the bounds of possibility, study the powers of actual objects.
The problem of transworld identity can be solved by individual essences [Forbes,G]
     Full Idea: The motivation for investigating individual essences should be obvious, since if every object has such an essence, the problem of elucidating transworld identity can be solved.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: It is important that, if necessary, the identities be 'individual', and not just generic, by sortal, or natural kind. We want to reason about (and explain) truths at the fine-grained level of the individual, not just at the broad level of generalisation.
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Counterpart theory is not good at handling the logic of identity [Forbes,G]
     Full Idea: The outstanding technical objection to counterpart-theoretic semantics concerns its handling of the logic of identity. In quantified S5 (the orthodox semantics) a = b → □(a = b) is valid, but 'a' must not attach to two objects.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 3.5)
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Haecceitism attributes to each individual a primitive identity or thisness [Forbes,G]
     Full Idea: Haecceitism attributes to each individual a primitive identity or thisness, as opposed to the sort of essentialism that gives non-trivial conditions sufficient for transworld identity.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 6.6)
     A reaction: 'Haecceitism' is the doctrine that things have primitive identity. A 'haecceity' is a postulated property which actually does the job. The key point of the view is that whatever it is is 'primitive', and not complex, or analysable. I don't believe it.
We believe in thisnesses, because we reject bizarre possibilities as not being about that individual [Forbes,G]
     Full Idea: The natural response to an unreasonable hypothesis of possibility for an object x, that in such a state of affairs it would not be x which satisfies the conditions, is evidence that we do possess concepts of thisness for individuals.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 9.4)
     A reaction: We may have a 'concept' of thisness, but we needn't be committed to the 'existence' of a thisness. There is a fairly universal intuition that cessation of existence of an entity when it starts to change can be a very vague matter.
12. Knowledge Sources / A. A Priori Knowledge / 6. A Priori from Reason
Aristotelians dislike the idea of a priori judgements from pure reason [Mares]
     Full Idea: Aristotelians tend to eschew talk about a special faculty of pure reason that is responsible for all of our a priori judgements.
     From: Edwin D. Mares (A Priori [2011], 08.9)
     A reaction: He is invoking Carrie Jenkins's idea that the a priori is knowledge of relations between concepts which have been derived from experience. Nice idea. We thus have an empirical a priori, integrated into the natural world. Abstraction must be involved.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Empiricists say rationalists mistake imaginative powers for modal insights [Mares]
     Full Idea: Empiricist critiques of rationalism often accuse rationalists of confusing the limits of their imaginations with real insight into what is necessarily true.
     From: Edwin D. Mares (A Priori [2011], 03.01)
     A reaction: See ideas on 'Conceivable as possible' for more on this. You shouldn't just claim to 'see' that something is true, but be willing to offer some sort of reason, truthmaker or grounding. Without that, you may be right, but you are on weak ground.
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
The most popular view is that coherent beliefs explain one another [Mares]
     Full Idea: In what is perhaps the most popular version of coherentism, a system of beliefs is a set of beliefs that explain one another.
     From: Edwin D. Mares (A Priori [2011], 01.5)
     A reaction: These seems too simple. My first response would be that explanations are what result from coherence sets of beliefs. I may have beliefs that explain nothing, but at least have the virtue of being coherent.
14. Science / B. Scientific Theories / 3. Instrumentalism
Operationalism defines concepts by our ways of measuring them [Mares]
     Full Idea: The central claim of Percy Bridgman's theory of operational definitions (1920s), is that definitions of certain scientific concepts are given by the ways that we have to measure them. For example, a straight line is 'the path of a light ray'.
     From: Edwin D. Mares (A Priori [2011], 02.9)
     A reaction: It is often observed that this captures the spirit of Special Relativity.
18. Thought / D. Concepts / 2. Origin of Concepts / b. Empirical concepts
Aristotelian justification uses concepts abstracted from experience [Mares]
     Full Idea: Aristotelian justification is the process of reasoning using concepts that are abstracted from experience (rather than, say, concepts that are innate or those that we associate with the meanings of words).
     From: Edwin D. Mares (A Priori [2011], 08.1)
     A reaction: See Carrie Jenkins for a full theory along these lines (though she doesn't mention Aristotle). This is definitely my preferred view of concepts.
18. Thought / D. Concepts / 4. Structure of Concepts / c. Classical concepts
The essence of a concept is either its definition or its conceptual relations? [Mares]
     Full Idea: In the 'classical theory' a concept includes in it those concepts that define it. ...In the 'theory theory' view the content of a concept is determined by its relationship to other concepts.
     From: Edwin D. Mares (A Priori [2011], 03.10)
     A reaction: Neither of these seem to give an intrinsic account of a concept, or any account of how the whole business gets off the ground.
19. Language / C. Assigning Meanings / 2. Semantics
In 'situation semantics' our main concepts are abstracted from situations [Mares]
     Full Idea: In 'situation semantics' individuals, properties, facts, and events are treated as abstractions from situations.
     From: Edwin D. Mares (Negation [2014], 6.1)
     A reaction: [Barwise and Perry 1983 are cited] Since I take the process of abstraction to be basic to thought, I am delighted to learn that someone has developed a formal theory based on it. I am immediately sympathetic to situation semantics.
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
Possible worlds semantics has a nice compositional account of modal statements [Mares]
     Full Idea: Possible worlds semantics is appealing because it gives a compositional analysis of the truth conditions of statements about necessity and possibility.
     From: Edwin D. Mares (A Priori [2011], 02.2)
     A reaction: Not sure I get this. Is the meaning composed by the gradual addition of worlds? If not, how is meaning composed in the normal way, from component words and phrases?
19. Language / D. Propositions / 3. Concrete Propositions
Unstructured propositions are sets of possible worlds; structured ones have components [Mares]
     Full Idea: An unstructured proposition is a set of possible worlds. ....Structured propositions contain entities that correspond to various parts of the sentences or thoughts that express them.
     From: Edwin D. Mares (A Priori [2011], 02.3)
     A reaction: I am definitely in favour of structured propositions. It strikes me as so obvious as to be not worth discussion - so I am obviously missing something here. Mares says structured propositions are 'more convenient'.
27. Natural Reality / C. Space / 3. Points in Space
Maybe space has points, but processes always need regions with a size [Mares]
     Full Idea: One theory is that space is made up of dimensionless points, but physical processes cannot take place in regions of less than a certain size.
     From: Edwin D. Mares (A Priori [2011], 06.7)
     A reaction: Thinkers in sympathy with verificationism presumably won't like this, and may prefer Feynman's view.