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10170
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While true-in-a-model seems relative, true-in-all-models seems not to be [Reck/Price]
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Full Idea:
While truth can be defined in a relative way, as truth in one particular model, a non-relative notion of truth is implied, as truth in all models.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
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A reaction:
[The article is actually discussing arithmetic] This idea strikes me as extremely important. True-in-all-models is usually taken to be tautological, but it does seem to give a more universal notion of truth. See semantic truth, Tarski, Davidson etc etc.
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10175
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Three types of variable in second-order logic, for objects, functions, and predicates/sets [Reck/Price]
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Full Idea:
In second-order logic there are three kinds of variables, for objects, for functions, and for predicates or sets.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
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A reaction:
It is interesting that a predicate seems to be the same as a set, which begs rather a lot of questions. For those who dislike second-order logic, there seems nothing instrinsically wicked in having variables ranging over innumerable multi-order types.
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10164
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Peano Arithmetic can have three second-order axioms, plus '1' and 'successor' [Reck/Price]
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Full Idea:
A common formulation of Peano Arithmetic uses 2nd-order logic, the constant '1', and a one-place function 's' ('successor'). Three axioms then give '1 is not a successor', 'different numbers have different successors', and induction.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
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A reaction:
This is 'second-order' Peano Arithmetic, though it is at least as common to formulate in first-order terms (only quantifying over objects, not over properties - as is done here in the induction axiom). I like the use of '1' as basic instead of '0'!
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10167
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Structuralism emerged from abstract algebra, axioms, and set theory and its structures [Reck/Price]
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Full Idea:
Structuralism has emerged from the development of abstract algebra (such as group theory), the creation of axiom systems, the introduction of set theory, and Bourbaki's encyclopaedic survey of set theoretic structures.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
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A reaction:
In other words, mathematics has gradually risen from one level of abstraction to the next, so that mathematical entities like points and numbers receive less and less attention, with relationships becoming more prominent.
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10169
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Relativist Structuralism just stipulates one successful model as its arithmetic [Reck/Price]
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Full Idea:
Relativist Structuralism simply picks one particular model of axiomatised arithmetic (i.e. one particular interpretation that satisfies the axioms), and then stipulates what the elements, functions and quantifiers refer to.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
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A reaction:
The point is that a successful model can be offered, and it doesn't matter which one, like having any sort of aeroplane, as long as it flies. I don't find this approach congenial, though having a model is good. What is the essence of flight?
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10179
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There are 'particular' structures, and 'universal' structures (what the former have in common) [Reck/Price]
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Full Idea:
The term 'structure' has two uses in the literature, what can be called 'particular structures' (which are particular relational systems), but also what can be called 'universal structures' - what particular systems share, or what they instantiate.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §6)
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A reaction:
This is a very helpful distinction, because it clarifies why (rather to my surprise) some structuralists turn out to be platonists in a new guise. Personal my interest in structuralism has been anti-platonist from the start.
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10182
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There are Formalist, Relativist, Universalist and Pattern structuralism [Reck/Price]
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Full Idea:
There are four main variants of structuralism in the philosophy of mathematics - formalist structuralism, relativist structuralism, universalist structuralism (with modal variants), and pattern structuralism.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §9)
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A reaction:
I'm not sure where Chihara's later book fits into this, though it is at the nominalist end of the spectrum. Shapiro and Resnik do patterns (the latter more loosely); Hellman does modal universalism; Quine does the relativist version. Dedekind?
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10168
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Formalist Structuralism says the ontology is vacuous, or formal, or inference relations [Reck/Price]
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Full Idea:
Formalist Structuralism endorses structural methodology in mathematics, but rejects semantic and metaphysical problems as either meaningless, or purely formal, or as inference relations.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §3)
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A reaction:
[very compressed] I find the third option fairly congenial, certainly in preference to rather platonist accounts of structuralism. One still needs to distinguish the mathematical from the non-mathematical in the inference relations.
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10178
|
Maybe we should talk of an infinity of 'possible' objects, to avoid arithmetic being vacuous [Reck/Price]
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Full Idea:
It is tempting to take a modal turn, and quantify over all possible objects, because if there are only a finite number of actual objects, then there are no models (of the right sort) for Peano Arithmetic, and arithmetic is vacuously true.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
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A reaction:
[compressed; Geoffrey Hellman is the chief champion of this view] The article asks whether we are not still left with the puzzle of whether infinitely many objects are possible, instead of existent.
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10177
|
Universalist Structuralism eliminates the base element, as a variable, which is then quantified out [Reck/Price]
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Full Idea:
Universalist Structuralism is eliminativist about abstract objects, in a distinctive form. Instead of treating the base element (say '1') as an ambiguous referring expression (the Relativist approach), it is a variable which is quantified out.
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From:
E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
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A reaction:
I am a temperamental eliminativist on this front (and most others) so this is tempting. I am also in love with the concept of a 'variable', which I take to be utterly fundamental to all conceptual thought, even in animals, and not just a trick of algebra.
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6237
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Fear of God is not conscience, which is a natural feeling of offence at bad behaviour [Shaftesbury]
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Full Idea:
Conscience is to find horribly offensive the reflection of any unjust action or behaviour; to have awe and terror of the Deity, does not, of itself, imply conscience; …thus religious conscience supposes moral or natural conscience.
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From:
3rd Earl of Shaftesbury (Inquiry Concerning Virtue or Merit [1699], II.II.I)
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A reaction:
The reply from religion would be that the Deity has implanted natural conscience in each creature, though this seems to deny our freedom of moral judgment. Personally I am inclined to think that values are just observations of the world - such as health.
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6234
|
If an irrational creature with kind feelings was suddenly given reason, its reason would approve of kind feelings [Shaftesbury]
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Full Idea:
If a creature wanting reason has many good qualities and affections, it is certain that if you give this creature a reflecting faculty, it will at the same instant approve of gratitude, kindness and pity.
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From:
3rd Earl of Shaftesbury (Inquiry Concerning Virtue or Merit [1699], I.III.III)
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A reaction:
A wonderful denunciation of the authority of reason, which must have influenced David Hume. I think, though, that the inverse of this case must be considered (if suddenly given feelings, they would fall in line with reasoning). We reason about feelings.
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6233
|
A person isn't good if only tying their hands prevents their mischief, so the affections decide a person's morality [Shaftesbury]
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Full Idea:
We do not say that he is a good man when, having his hands tied up, he is hindered from doing the mischief he designs; …hence it is by affection merely that a creature is esteemed good or ill, natural or unnatural.
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From:
3rd Earl of Shaftesbury (Inquiry Concerning Virtue or Merit [1699], I.II.I)
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A reaction:
Note that he more or less equates being morally 'ill' with being 'unnatural'. We tend to reserve 'unnatural' for extreme or perverse crimes. Personally I would place more emphasis on evil judgements, and less on evil feelings.
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6235
|
Self-interest is not intrinsically good, but its absence is evil, as public good needs it [Shaftesbury]
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Full Idea:
Though no creature can be called good merely for possessing the self-preserving affections, it is impossible that public good can be preserved without them; so that a creature wanting in them is wanting in natural rectitude, and may be esteemed vicious.
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From:
3rd Earl of Shaftesbury (Inquiry Concerning Virtue or Merit [1699], II.I.III)
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A reaction:
Aristotle held a similar view (Idea 92). I think maybe Shaftesbury was the last call of the Aristotelians, before being engulfed by utilitarians and Kantians. This idea is at the core of capitalism.
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