415 words on Uni
Yesterday in the Wittgenstein seminar we discussed § 253 of the philosophical investigations which is about identity or being equal. The German language sort of raises you with an awareness of that difference, providing two versions of the same
| German | English | Objective-C |
| der selbe | identical | a == b |
| der gleiche | equal to/the same as | [a isEqual:b] |
During the discussion I learned about a neat way to define the identity of two objects, say, a chair I saw yesterday and the chair I see now. This identity cannot be defined by the properties of the existing object as the object may change or it may be replaced by an different object which has all the same properties. Rather, you'd define the identity of the two chairs by requiring that there be a continuous path in space-time joining them. This wasn't really related to Wittgenstein but I considered it a clever idea.
Apparently the importance of having a good notion of identity goes back to Frege's Grundlagen der Arithmetik (see myprotocol of our seminar on this a couple of years ago for reference - according to our server logs another quite popular file on our server). In § 62 he states
Wenn uns das Zeichen a einen Gegenstand bezeichnen soll, so müssen wir ein Kennzeichen haben, welches überall entscheidet, ob b dasselbe sei wie a, wenn es auch nicht immer in unserer Macht steht, dies Kennzeichen anzuwenden.
Finally, I simply have to quote the last bit of §253 in Wittgenstein's philosophical investigations:
I have seen a person in a discussion on this subject strike himself on the breast and say: "But surely another person can't have this pain!" - The answer to this is that one does not define a criterion of identity by emphatic stressing of the word "this". Rather, what the emphasis does is to suggest the case in which we are familiar with such a criterion of identity, but have to be reminded of it.
... or in the original:
Ich habe gesehen, wie jemand in einer Diskussion über diesen Gegenstand sich an die Brust schlug und sagte:"Ander der Andre kann doch nicht diesen Schmerz haben!" - Die Antwort darauf ist, daß man durch das emphatische Betonen des Wortes "diesen" kein Kriterium der Identität definiert. Die Emphase spiegelt uns vielmehr nur den Fall vor, daß ein solches Kriterium uns geläufig ist, wir aber dran erinnert werden müssen.
Surely, Wittgenstein was a humorous person, subtly... and theres even a blog on the investiagations.