Saturday, March 12, 2011

On discovering what we already knew

A priori textual analysis continues to amuse. David Brightly has objected that indiscernibility of identicals (Leibniz II) applies only to names, not to descriptions like 'the murderer' or 'Shakespeare', when used in the sense of 'the man who wrote the plays'. Nishadani has objected that 'Shakespeare' is not the name of a single person.

I will discuss these objections later. Meanwhile, another puzzle. If Leibniz II is correct, we can substitute any two proper names so long as they are names for the same person, salva veritate. Thus, if Shakespeare and Edward de Vere (another contender for the identity) were the same person, it follows that
  • We have always known that Shakespeare was De Vere, since we have always known that Shakespeare was Shakespeare, a logical truth.
  • We could never discover that Shakespeare was De Vere, since you cannot discover what you already know.

And so on.


David Brightly said...

This is pretty complicated:

1. The sense/reference distinction. I can know Cicero is an orator but brought face to face with him I may not know that the man in front of me is an orator. A witness might report this as my not knowing that Cicero is an orator. Who is right?
2. The predicate '_is known by x to be F' is Cambridge enough but when F takes the form 'identical to y' the sense/reference distinction raises its head in a second place.
3. There seems a connection between Fregean sense/reference and Russellian knowledge by description/acquaintance. To know the referent of a name seems to be acquainted with it. But can we be acquainted with an historical figure? Or a fictional one?

Quite a thicket here! In direct speech there seems no problem:

1. "I have always known S was S." Odd thing to say maybe but OK.
2. "I have learned DV was S, so I now know DV wrote TT".

Edward Ockham said...

The question is whether Leibniz II holds for ordinary proper names or not. It is generally agreed that it holds for logically proper names, but that it does not hold for definite descriptions, as is easily shown (tomorrow).

The question is whether ordinary proper names are disguised descriptions or not.

I'm seeing this whole thread as a negative argument against the view that proper names are logically proper, and thus negatively supporting the view that they signify singular concepts.