19 ideas
| 17311 | Real definitions don't just single out a thing; they must also explain its essence [Koslicki] |
| Full Idea: A statement expressing a real definition must also accomplish more than simply to offer two different ways of singling out the same entity, since the definiens must also be explanatory of the essential nature of the definiendum. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.4) | |
| A reaction: This is why Aristotelian definitions are not just short lexicographical definitions, but may be quite length. Effectively, a definition IS an explanation. |
| 10482 | The logic of ZF is classical first-order predicate logic with identity [Boolos] |
| Full Idea: The logic of ZF Set Theory is classical first-order predicate logic with identity. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.121) | |
| A reaction: This logic seems to be unable to deal with very large cardinals, precisely those that are implied by set theory, so there is some sort of major problem hovering here. Boolos is fairly neutral. |
| 10492 | A few axioms of set theory 'force themselves on us', but most of them don't [Boolos] |
| Full Idea: Maybe the axioms of extensionality and the pair set axiom 'force themselves on us' (Gödel's phrase), but I am not convinced about the axioms of infinity, union, power or replacement. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.130) | |
| A reaction: Boolos is perfectly happy with basic set theory, but rather dubious when very large cardinals come into the picture. |
| 10485 | Naïve sets are inconsistent: there is no set for things that do not belong to themselves [Boolos] |
| Full Idea: The naïve view of set theory (that any zero or more things form a set) is natural, but inconsistent: the things that do not belong to themselves are some things that do not form a set. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.127) | |
| A reaction: As clear a summary of Russell's Paradox as you could ever hope for. |
| 10484 | The iterative conception says sets are formed at stages; some are 'earlier', and must be formed first [Boolos] |
| Full Idea: According to the iterative conception, every set is formed at some stage. There is a relation among stages, 'earlier than', which is transitive. A set is formed at a stage if and only if its members are all formed before that stage. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.126) | |
| A reaction: He gives examples of the early stages, and says the conception is supposed to 'justify' Zermelo set theory. It is also supposed to make the axioms 'natural', rather than just being selected for convenience. And it is consistent. |
| 10491 | Infinite natural numbers is as obvious as infinite sentences in English [Boolos] |
| Full Idea: The existence of infinitely many natural numbers seems to me no more troubling than that of infinitely many computer programs or sentences of English. There is, for example, no longest sentence, since any number of 'very's can be inserted. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.129) | |
| A reaction: If you really resisted an infinity of natural numbers, presumably you would also resist an actual infinity of 'very's. The fact that it is unclear what could ever stop a process doesn't guarantee that the process is actually endless. |
| 10483 | Mathematics and science do not require very high orders of infinity [Boolos] |
| Full Idea: To the best of my knowledge nothing in mathematics or science requires the existence of very high orders of infinity. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.122) | |
| A reaction: He is referring to particular high orders of infinity implied by set theory. Personally I want to wield Ockham's Razor. Is being implied by set theory a sufficient reason to accept such outrageous entities into our ontology? |
| 17312 | It is more explanatory if you show how a number is constructed from basic entities and relations [Koslicki] |
| Full Idea: Being the successor of the successor of 0 is more explanatory than being predecessor of 3 of the nature of 2, since it mirrors more closely the method by which 2 is constructed from a basic entity, 0, and a relation (successor) taken as primitive. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.4) | |
| A reaction: This assumes numbers are 'constructed', which they are in the axiomatised system of Peano Arithmetic, but presumably the numbers were given in ordinary experience before 'construction' occurred to anyone. Nevertheless, I really like this. |
| 10490 | Mathematics isn't surprising, given that we experience many objects as abstract [Boolos] |
| Full Idea: It is no surprise that we should be able to reason mathematically about many of the things we experience, for they are already 'abstract'. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.129) | |
| A reaction: He has just given a list of exemplary abstract objects (Idea 10489), but I think there is a more interesting idea here - that our experience of actual physical objects is to some extent abstract, as soon as it is conceptualised. |
| 17314 | The relata of grounding are propositions or facts, but for dependence it is objects and their features [Koslicki] |
| Full Idea: The relata of the grounding relation are typically taken to be facts or propositions, while the relata of ontological dependence ...are objects and their characteristics, activities, constituents and so on. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.5 n25) | |
| A reaction: Interesting. Good riddance to propositions here, but this seems a bit unfair to facts, since I take facts to be in the world. Audi's concept of 'worldly facts' is what we need here. |
| 10488 | It is lunacy to think we only see ink-marks, and not word-types [Boolos] |
| Full Idea: It's a kind of lunacy to think that sound scientific philosophy demands that we think that we see ink-tracks but not words, i.e. word-types. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.128) | |
| A reaction: This seems to link him with Armstrong's mockery of 'ostrich nominalism'. There seems to be some ambiguity with the word 'see' in this disagreement. When we look at very ancient scratches on stones, why don't we always 'see' if it is words? |
| 10487 | I am a fan of abstract objects, and confident of their existence [Boolos] |
| Full Idea: I am rather a fan of abstract objects, and confident of their existence. Smaller numbers, sets and functions don't offend my sense of reality. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.128) | |
| A reaction: The great Boolos is rather hard to disagree with, but I disagree. Logicians love abstract objects, indeed they would almost be out of a job without them. It seems to me they smuggle them into our ontology by redefining either 'object' or 'exists'. |
| 10489 | We deal with abstract objects all the time: software, poems, mistakes, triangles.. [Boolos] |
| Full Idea: We twentieth century city dwellers deal with abstract objects all the time, such as bank balances, radio programs, software, newspaper articles, poems, mistakes, triangles. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.129) | |
| A reaction: I find this claim to be totally question-begging, and typical of a logician. The word 'object' gets horribly stretched in these discussions. We can create concepts which have all the logical properties of objects. Maybe they just 'subsist'? |
| 17313 | Modern views want essences just to individuate things across worlds and times [Koslicki] |
| Full Idea: According to the approach of Plantinga, Forbes and Mackie, the primary job of essences is to individuate the entities whose essences they are across worlds and times at which these entities exist. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.4 n13) | |
| A reaction: A helpful simplification of what is going on. I wish those authors would just say this one their first pages. They all get in a right tangle, because individuation is either too easy, or hopeless. 'Tracking' is a good word for this game. |
| 17309 | For Fine, essences are propositions true because of identity, so they are just real definitions [Koslicki] |
| Full Idea: Fine assumes that essences can be identified with collections of propositions that are true in virtue of the identity of a particular object, or objects. ...There is not, on this approach, much of a distinction between essences and real definitions. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.4) | |
| A reaction: This won't do, because the essence of a physical object is not a set of propositions, it is some aspects of the object itself, which are described in a definition. Koslicki notes that psuché is an essence, and the soul is hardly a set of propositions! |
| 17315 | We need a less propositional view of essence, and so must distinguish it clearly from real definitions [Koslicki] |
| Full Idea: To make room for a less propositional conception of essence than that assumed by Fine, I urge that we distinguish more firmly between essences and real definitions (which state these essences in the form of propositions). | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.6) | |
| A reaction: Yes. The idea that essence is just a verbal or conceptual entity would be utterly abhorrent to Aristotle (a hero for Fine), and it is anathema to me too. We intend essences to be in the world (even if we are deceived about that). They explain! |
| 17317 | A good explanation captures the real-world dependence among the phenomena [Koslicki] |
| Full Idea: It is plausible to think that an explanation, when successful, captures or represents (by argument, or a why? question) an underlying real-world relation of dependence which obtains among the phenomena cited. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.6) | |
| A reaction: She cites causal dependence as an example. I'm incline to think that 'grounding' is a better word for the target of good explanations than is 'dependence' (which can, surely, be mutual, where ground has the directionality needed for explanation). |
| 17316 | We can abstract to a dependent entity by blocking out features of its bearer [Koslicki] |
| Full Idea: In 'feature dependence', the ontologically dependent entity may be thought of as the result of a process of abstraction which takes the 'bearer' as its starting point and arrives at the abstracted entity by blocking out all the irrelevant features. | |
| From: Kathrin Koslicki (Varieties of Ontological Dependence [2012], 7.6) | |
| A reaction: She seems unaware that this is traditional abstraction, found in Aristotle, and a commonplace of thought until Frege got his evil hands on abstraction and stole it for other purposes. I'm a fan. |
| 19399 | Prime matter is nothing when it is at rest [Leibniz] |
| Full Idea: Primary matter is nothing if considered at rest. | |
| From: Gottfried Leibniz (Aristotle and Descartes on Matter [1671], p.90) | |
| A reaction: This goes with Leibniz's Idea 13393, that activity is the hallmark of existence. No one seems to have been able to make good sense of prime matter, and it plays little role in Aristotle's writings. |