display all the ideas for this combination of philosophers
14 ideas
| 11843 | Identity over a time and at a time aren't different concepts [Wiggins] |
| Full Idea: People often speak of identity over time and distinguish it from identity at a time. But identity is just identity. | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 2.3) | |
| A reaction: I myself am guilty of such usage, but it doesn't imply a commitment to a multivocal concept. The epistemological issues (of explaining what it is now, and simply reidentifying it later) seem profoundly different. Hume only admits identity over time. |
| 11864 | Hesperus=Hesperus, and Phosphorus=Hesperus, so necessarily Phosphorus=Hesperus [Wiggins] |
| Full Idea: The simple proof (from Ruth Barcan Marcus) is: Hesperus is necessarily Hesperus, so if Phosphorus is Hesperus, then Phosphorus is necessarily Hesperus. | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 4.3) | |
| A reaction: This is the famous idea which she noticed well before Kripke. The point is that the simple logic of the case bestows a necessity on the identity. We shouldn't be confused by the a posteriori and contingent nature of the discovery. |
| 16498 | Identity cannot be defined, because definitions are identities [Wiggins] |
| Full Idea: Since any definition is an identity, identity itself cannot be defined. | |
| From: David Wiggins (Sameness and Substance [1980], 1.2 n7) | |
| A reaction: This sounds too good to be true! I can't think of an objection, so, okay, identity cannot possibly be defined. We can give synonyms for it, I suppose. [Wrong, says Rumfitt! Definitions can also be equivalences!] |
| 16497 | Leibniz's Law (not transitivity, symmetry, reflexivity) marks what is peculiar to identity [Wiggins] |
| Full Idea: The principle of Leibniz's Law marks off what is peculiar to identity and differentiates it in a way in which transitivity, symmetry and reflexivity (all shared by 'exact similarity, 'equality in pay', etc.) do not. | |
| From: David Wiggins (Sameness and Substance [1980], 1.2) |
| 16502 | Identity is primitive [Wiggins] |
| Full Idea: Identity is a primitive notion. | |
| From: David Wiggins (Sameness and Substance [1980], 2.1) | |
| A reaction: To be a true primitive it would have to be univocal, but it seems to me that 'identity' comes in degrees. The primitive concept is the minimal end of the degrees, but there are also more substantial notions of identity. |
| 11831 | The formal properties of identity are reflexivity and Leibniz's Law [Wiggins] |
| Full Idea: The formal properties of identity are the reflexivity of identity, and Leibniz's Law (if x is the same as y, then whatever is true of one is true of the other). | |
| From: David Wiggins (Sameness and Substance Renewed [2001], Pr.2) | |
| A reaction: Presumably transitivity will also apply, and, indeed, symmetry. He seems to mean something like the 'axiomatic formal properties'. |
| 14362 | Relative Identity is incompatible with the Indiscernibility of Identicals [Wiggins, by Strawson,P] |
| Full Idea: Wiggins argues that Geach's Relative Identity is incompatible with the formal properties of identity, which include, besides transitivity, symmetry and reflexivity, the complete community of properties defined by the Indiscernibility of Identicals. | |
| From: report of David Wiggins (Sameness and Substance Renewed [2001]) by Peter F. Strawson - Review of 'Sameness and Substance' p.603 | |
| A reaction: The tricky part is that Wiggins then goes on to say that identity depends on sortals, which sounds very close to the Geach view. I find disentangling them tricky. See Idea 14363 for a helpful comment from Strawson. |
| 11838 | Relativity of Identity makes identity entirely depend on a category [Wiggins] |
| Full Idea: The thesis of Relativity of Identity (which I steadfastly oppose) ..suggests that it makes all the difference to keeping track of continuants through space and time which concept one subsumes something under. | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 1.1) | |
| A reaction: [Geach I take to be the villain of this idea] The point is that identity is entirely relative to the sortal concept, where Wiggins wants to make identity a combination of the object itself and our concept of it (I think). |
| 11847 | To identify two items, we must have a common sort for them [Wiggins] |
| Full Idea: As a necessary condition of the truth of an identity claim, some common sort f will have to be found to which they each belong. That is the point at which the primary question of identity can come into focus. | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 2.2) | |
| A reaction: This is the plainest English expression I can find of Wiggins's main thesis. He maintains this thesis, while adamantly denying the idea that identity consists entirely of falling under a concept. |
| 16521 | A is necessarily A, so if B is A, then B is also necessarily A [Wiggins] |
| Full Idea: The famous proof of Barcan Marcus about necessity of identity comes down to simply this: Hesperus is necessarily Hesperus, so if Phosphorus is Hesperus, Phosphorus is necessarily Hesperus. | |
| From: David Wiggins (Sameness and Substance [1980], 4.3) | |
| A reaction: Since the identity of Hesperus and Phosphorus was an a posteriori discovery, this was taken to be the inception of the idea that there are a posteriori necessities. The conclusion seems obvious. One thing is necessarily one thing. |
| 16505 | By the principle of Indiscernibility, a symmetrical object could only be half of itself! [Wiggins] |
| Full Idea: The full Identity of Indiscernibles excludes the existence in this world of a symmetrical object, which is reduced to half of itself by the principle. If symmetrical about all planes that bisect it, it is precluded altogether from existence. | |
| From: David Wiggins (Sameness and Substance [1980], 2.2) | |
| A reaction: A really nice objection. Do the parts even need to be symmetrical? My eyeballs can't be identical to one another, presumably. Electrons already gave the principle big trouble. |
| 11839 | Do both 'same f as' and '=' support Leibniz's Law? [Wiggins] |
| Full Idea: Is Leibniz's Law as true for 'is the same as' as it is for '='? | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 1.2) | |
| A reaction: [By Leibniz's Law he means if they are the same, they support the same truths] |
| 11845 | Substitutivity, and hence most reasoning, needs Leibniz's Law [Wiggins] |
| Full Idea: Leibniz's Law underwrites the substitutivity of identity and this is a principle not long dispensable in any form of reasoning. | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 2.7) | |
| A reaction: Thus the modern fashion of deriving our metaphysics from our logic. Presumably we can derive it from our epistemology too, or even from our intuitions, if we thought they were good enough as evidence. |
| 16494 | We want to explain sameness as coincidence of substance, not as anything qualitative [Wiggins] |
| Full Idea: The notion of sameness or identity that we are to elucidate is not that of any degree of qualitative similarity but of coincidence as a substance - a notion as primitive as predication. | |
| From: David Wiggins (Sameness and Substance [1980], Pre 2) | |
| A reaction: This question invites an approach to identity through our descriptions of it, rather than to the thing itself. There is no problem in ontology of two substances being 'the same', because they are just one substance. |