16 ideas
| 15091 | Restrict 'logical truth' to formal logic, rather than including analytic and metaphysical truths [Shoemaker] |
| Full Idea: I favour restricting the term 'logical truth' to what logicians would count as such, excluding both analytic truths like 'Bachelors are unmarried' and Kripkean necessities like 'Gold is an element'. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], I) | |
| A reaction: I agree. There is a tendency to splash the phrases 'logical truth' and 'logical necessity around in vague ways. I take them to strictly arise out of the requirements of formal systems of logic. |
| 10580 | Mathematics is both necessary and a priori because it really consists of logical truths [Yablo] |
| Full Idea: Mathematics seems necessary because the real contents of mathematical statements are logical truths, which are necessary, and it seems a priori because logical truths really are a priori. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 10) | |
| A reaction: Yablo says his logicism has a Kantian strain, because numbers and sets 'inscribed on our spectacles', but he takes a different view (in the present Idea) from Kant about where the necessity resides. Personally I am tempted by an a posteriori necessity. |
| 10579 | Putting numbers in quantifiable position (rather than many quantifiers) makes expression easier [Yablo] |
| Full Idea: Saying 'the number of Fs is 5', instead of using five quantifiers, puts the numeral in quantifiable position, which brings expressive advantages. 'There are more sheep in the field than cows' is an infinite disjunction, expressible in finite compass. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 08) | |
| A reaction: See Hofweber with similar thoughts. This idea I take to be a key one in explaining many metaphysical confusions. The human mind just has a strong tendency to objectify properties, relations, qualities, categories etc. - for expression and for reasoning. |
| 10577 | Concrete objects have few essential properties, but properties of abstractions are mostly essential [Yablo] |
| Full Idea: Objects like me have a few essential properties, and numerous accidental ones. Abstract objects are a different story. The intrinsic properties of the empty set are mostly essential. The relations of numbers are also mostly essential. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 01) |
| 10578 | We are thought to know concreta a posteriori, and many abstracta a priori [Yablo] |
| Full Idea: Our knowledge of concreta is a posteriori, but our knowledge of numbers, at least, has often been considered a priori. | |
| From: Stephen Yablo (Abstract Objects: a Case Study [2002], 02) |
| 15095 | A property's causal features are essential, and only they fix its identity [Shoemaker] |
| Full Idea: The view I now favour says that the causal features of a property, both forward-looking and backward-looking, are essential to it. And it says that properties having the same causal features are identical. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], III) | |
| A reaction: In this formulation we have essentialism about properties, as well as essentialism about the things which have the properties. |
| 15097 | I claim that a property has its causal features in all possible worlds [Shoemaker] |
| Full Idea: The controversial claim of my theory is that the causal features of properties are essential to them - are features that they have in all possible worlds. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], III) | |
| A reaction: One problem is that a property can come in degrees, so what degree of the property is necessary to it? It is better to assign this claim to the fundamental properties (which are best called 'powers'). |
| 15094 | I now deny that properties are cluster of powers, and take causal properties as basic [Shoemaker] |
| Full Idea: I now reject the formulation of the causal theory which says that a property is a cluster of conditional powers. That has a reductionist flavour, which is a cheat. We need properties to explain conditional powers, so properties won't reduce. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], III) | |
| A reaction: [compressed wording] I agree with Mumford and Anjum in preferring his earlier formulation. I think properties are broad messy things, whereas powers can be defined more precisely, and seem to have more stability in nature. |
| 13160 | To exist and be understood, a multitude must first be reduced to a unity [Leibniz] |
| Full Idea: A plurality of things can neither be understood nor can exist unless one first understands the thing that is one, that to which the multitude necessarily reduces. | |
| From: Gottfried Leibniz (Notes on Comments by Fardella [1690], Prop 3) | |
| A reaction: Notice that it is our need to understand which imposes the unity on the multitude. It is not just some random fiction, or a meaningless mechanical act of thought. |
| 13161 | Substances are everywhere in matter, like points in a line [Leibniz] |
| Full Idea: There are substances everywhere in matter, just as points are everywhere in a line. | |
| From: Gottfried Leibniz (Notes on Comments by Fardella [1690], Clarif) | |
| A reaction: Since Leibniz is unlikely to believe in the reality of the points, we must wonder whether he was really committed to this infinity of substances. The more traditional notion of substance is always called 'substantial form' by Leibniz. |
| 15099 | If something is possible, but not nomologically possible, we need metaphysical possibility [Shoemaker] |
| Full Idea: If it is possible that there could be possible states of affairs that are not nomologically possible, don't we therefore need a notion of metaphysical possibility that outruns nomological possibility? | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VI) | |
| A reaction: Shoemaker rejects this possibility (p.425). I sympathise. So there is 'natural' possibility (my preferred term), which is anything which stuff, if it exists, could do, and 'logical' possibility, which is anything that doesn't lead to contradiction. |
| 15101 | Once you give up necessity as a priori, causal necessity becomes the main type of necessity [Shoemaker] |
| Full Idea: Once the obstacle of the deeply rooted conviction that necessary truths should be knowable a priori is removed, ...causal necessity is (pretheoretically) the very paradigm of necessity, in ordinary usage and in dictionaries. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VII) | |
| A reaction: The a priori route seems to lead to logical necessity, just by doing a priori logic, and also to metaphysical necessity, by some sort of intuitive vision. This is a powerful idea of Shoemaker's (implied, of course, in Kripke). |
| 15098 | Empirical evidence shows that imagining a phenomenon can show it is possible [Shoemaker] |
| Full Idea: We have abundant empirical evidence that when we can imagine some phenomenal situation, e.g., imagine things appearing certain ways, such a situation could actually exist. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VI) | |
| A reaction: There seem to be good reasons for holding the opposite view too. We can imagine gold appearing to be all sorts of colours, but that doesn't make it possible. What does empirical evidence really tell us here? |
| 15100 | Imagination reveals conceptual possibility, where descriptions avoid contradiction or incoherence [Shoemaker] |
| Full Idea: Imaginability can give us access to conceptual possibility, when we come to believe situations to be conceptually possible by reflecting on their descriptions and seeing no contradiction or incoherence. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VI) | |
| A reaction: If take the absence of contradiction to indicate 'logical' possibility, but the absence of incoherence is more interesting, even if it is a bit vague. He is talking of 'situations', which I take to be features of reality. A priori synthetic? |
| 15096 | 'Grue' only has causal features because of its relation to green [Shoemaker] |
| Full Idea: Perhaps 'grue' has causal features, but only derivatively, in virtue of its relation to green. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], III) | |
| A reaction: I take grue to be a behaviour, and not a property at all. The problem only arises because the notion of a 'property' became too lax. Presumably Shoemaker should also mention blue in his account. |
| 15093 | We might say laws are necessary by combining causal properties with Armstrong-Dretske-Tooley laws [Shoemaker] |
| Full Idea: One way to get the conclusion that laws are necessary is to combine my view of properties with the view of Armstrong, Dretske and Tooley, that laws are, or assert, relations between properties. | |
| From: Sydney Shoemaker (Causal and Metaphysical Necessity [1998], I) | |
| A reaction: This is interesting, because Armstrong in particular wants the necessity to arise from relations between properties as universals, but if we define properties causally, and make them necessary, we might get the same result without universals. |