Kripke's Necessary, A Posteriori Statements

This video looks at Saul Kripke's argument for Necessary, a posteriori statements such as Hesperus is Phosphorus.

This series looks at whether the necessary vs contingent, analytic vs synthetic, and a priori vs a posteriori distinctions actually can map onto each other and if they are even useful with the arguments of Immanuel Kant, W. V. O Quine, and Saul Kripke.

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Information for this video gathered from The Stanford Encyclopedia of Philosophy, The Internet Encyclopedia of Philosophy, The Cambridge Dictionary of Philosophy, The Oxford Dictionary of Philosophy and more! (#Kripke #PhilosophyOfLanguage)

[richardstrum]

I haven't read Kripke himself, but, from what I saw in this video, the conclusion that there are necessary a posteriori statement seems to me to result from equivocation. "Phosphorus" ostensively refers to "that dot of light in the morning" and "Hesperus" to "that dot of light in the evening." Then further observation showed that they are both the same physical object. But there is nothing necessary about that. From our perspective, further observation could have shown them to be two different bodies. It just happens to be that we live in a world where they are the same thing.

Now that we know that they are the same, if you want to redefine "Phosphorus" as "Hesperus, " that's fine, but now you've just got an analytic a priori statement.

[cliffordhodge]

Although I have always been suspicious of the basic distinctions involving aprioricity, analyticity, and necessity, that suspicion probably derives mainly (entirely?) from the fact that they always deal with propositions rather than with what we might call raw brute facts - states of affairs in the world quite independent of any intensional stance. That is why I am uncomfortable with the notion of a rigid designator presented as a linguistic metaphysical marker. If we assume that naming depends on ostension, and propose that names like 'Hesperus' and 'Phosphorous' are logically preceded by a token of "that is the morning star, " and a token of, "that is the evening star, " respectively, we now have a more dubious claim for a necessary truth of something like, "That (in the morning) is identical with ... that (in the evening)." Nothing here is different about the thing - Venus - which is pointed to, but it suddenly seems much more plausible that the first token pointing was to Venus, and the second pointing was to Star X. This, I think, is because pure ostension is at once the most pure and unfailing methods of rigid designation, de re reference, and yet the most vacuous, as we might say, method of designation. In other words, the use of a language name, like 'Morning Star' or 'Venus' seems to always carry with it some assumption of properties, whereas 'that' is a sort of indexing tool for picking out a set of space-time points paired with an intension which may be totally uninformed about what is pointed at. As Kripke said, when I point and baptize by saying, "That is a tiger, " I may be pointing at a tiger-looking robot, not an animal at all. And so we may forever after be guilty of collective misuse of the word 'tiger'.

[cliffordhodge]

Regarding the essentialism discussion, the idea that there are no essential properties has, in my experience, always been presented as the view that there is also no non-essential property for an object. I.e., it does away with the distinction essential/non-essential as being a false distinction, because every one of your properties is one you must have to be you rather than something even very slightly different from you. It is as in this story: Adam asks God, "Lord, why could you not have made a man with all my properties save that he does not fall into sin?" And God answers, "Why Adam, don't you see? If I had done that, it would not have been you."

[martinbennett]

'Two sides of the same coin', we have an idiom for necessary a posteriori concepts.

[andreasbrey]

Well, there is a lot missing here IMHO:
- ref to Gottlob Frege: Begriffsschrift (delta of meaning and sense),
- ref to Immanuel Kant (magic quadrant of "transzendentale Erkenntnis"),
- discuss if Kant and Kripke share the same essence of the term 'necessary a priori" (metaphysical vs. analytic),
- there are some inconsistencies with the modal logic possible world theory and 'genesis' of terms / tokens, don't you think?

thank you for your video.

[isabelrenteria]

Thanks for your video! <3
When I saw him, I discovered that the analitic philosophy is more
understandable in original lenguaje: the english :)

[iangoddard]

Some issues people have with this fine video I think could have been avoided if it was made clear how, or simply just that, the topic is anchored in formal logic. Otherwise it may come across to some unfamiliar therewith as pie-in-the-sky philosophical meanderings.

[kravitzn]

"Hesperus is Phosphorus" is a case of equivocation. The designator "Hesperus" picks out that heavenly body seen in the evening, and "Phosphorus" picks out the one seen in the morning. These need not necessarily refer to the same heavenly body. They happen to in this world.

[zubrz]

Or I don't understand what is meant by "possible worlds", how much can we change in them so that we lose rigidity.

[chad]

This is probably a stupid question, but if Hesperus doesn’t exist in all possible worlds then how can the statement “Hesperus is phosphorus” be true in all possible worlds?

[milliern]

Presumably, a posteriori negative truths are discussed in "Naming and Necessity, " but where and when do "rigid designators" first appear? Thanks!

[KManAbout]

Yeah, I don't think I buy that these are necessary a posteriori truths. I think this example points to a problem with rigid designators in the first place. For example, I could think of a possible world in which Hesperus is not Phosphorus. Two rigid designators if they are truly separate I don't believe can be necessarily identical. For example, I could be Superman and not Clark Kent. Or Spiderman could be John J. Jameson instead of Peter Parker. Rigid Designators, I believe, seem to include some belief of essentialism when it comes to an object if you accept necessary a posteriori truths. However, it doesn't seem to be the case with the definition given by Kripke earlier so there isn't a mechanism that makes Hesperus == Phosphorus. Particular Rigid Designators don't have any essential qualities and thus can't contain truths of any kind except perhaps those a priori and even those I am skeptical of.

[matthewmelson]

I agree that there might be truths that exist across all possible worlds. Such as 1+1=2. But I think those examples givin are pretty bad.