Sunday, November 4, 2012

[PHI 3000] Is it necessarily true that Peter Parker = Spider-man?

In Naming and Necessity, Kripke argues that true identity statements in which the identity sign is flanked by two rigid designators are necessarily true. For example, ‘Hesperus = Phosphorus’ is necessarily true, according to Kripke, although it was discovered a posteriori to be true, since ‘Hesperus’ is a name that was given to a heavenly body seen in the evening, and ‘Phosphorus’ is a name that was, unknown to the first users of the name, given to that same heavenly body seen in the morning. The heavenly body is Venus.

Now, consider the following identity statement:
Peter Parker = Spider-man
This identity statement is true in the world in which Peter Parker exists. But is it necessarily true (i.e., is it true in all possible worlds)?

Couldn't one conceive of a world in which the person who is bitten by a radioactive spider is not Peter Parker, but rather Harry Osborn? And if so, wouldn't it be the case that, in that possible world, 'Peter Parker = Spider-man' is false and 'Harry Osborn = Spider-man' is true? And if so, wouldn't it then be the case that 'Peter Parker = Spider-man' is not necessarily true even though 'Pater Parker' and 'Spider-man' are rigid designators?


  1. So I take it an appropriate Kripke-ish response might say that, in your example, you are incorrectly conceiving of the name Spider-man as being a descriptive name. That is, you're suggesting that Spider-man means 'the person who acquires certain powers as a result of being bitten by a radioactive spider.'
    Thus, Peter Parker = Spider-man cannot be necessarily true, because we can easily imagine Peter Parker never being bitten by a radioactive spider.

    However, using Kripke's idea of rigid designation, we should *not* say that Spider-man = the person who acquires certain powers as a result of being bitten by a radioactive spider. Instead, we should look at who, in the actual world, Spider-man refers to. Then, by definition of rigid designation, in any possible world x, the term Spider-man still refers to that object which it corresponds to in the actual world (even if, in possible world x people happen to use the same term "Spider-man" for the person bitten by a radioactive spider... who happens to be Harry Osbourne).

    Essentially, as 1)Spider-man and Peter Parker refer to the same object in the actual world, 2) each name is a rigid designator, and 3) rigid designators (by definition) pick out the same object in all possible worlds... Kripke will triumphantly declare that the statement Spider-man = Peter Parker is true in all possible worlds (because each name will pick out the same individual in all possible worlds) and, therefore, it is necessarily true.

    So I think Kripke would have a response readily available, granted the concept of rigid designation. The real question, I think, is whether the concept of rigid designation can withstand some good metaphysical probing. Why buy it?

    ...But anyway. I am excited that my newly acquired philosophy of language knowledge is being put to good use!

    1. Excellent question, Annette. Do you buy it?


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