Friday, May 30, 2008

Fictional objects

There is more stuff on existence going on at Bill Vallicella's place. This time, 'fictional objects', which I cannot bring myself to take seriously.

The gist of it is, characters such as Bilbo, creatures such as hobbits and imaginary places such as Hobbiton are objects in some sense. And if they are, and given that the fiction is all the information we have about them, these objects must be in some sense incomplete. We are not told what Bilbo's mother was called. So she is incomplete, not having a name. Indeed, we are not told whether Bilbo had a mother at all. So, he is incomplete. And so on.
Now this really is language on holiday. Suppose I write:

In 1998 a planet the size of Jupiter was miraculously created in the orbit between the Earth and Venus.

Does writing this miraculously create a fictional object the size of Jupiter? And does it get created just now, in May 2008, or 10 years ago in 1998, when it was claimed to have been created? Or should we be more prosaic and say that no object was created at all? For it says above that such a planet was created, and, as far as we know, no such planet ever was.

And if we do believe some object has just been created, is it really incomplete in the sense that Vallicella et alia suggest? Isn't it just the reverse? I can go on to make any false statement I like about this planet: it is a gas giant, not a gas giant, has frozen helium at its core, a black hole, whatever. Since any statement 'about' this planet has to be false, it does not matter what I say. All are equally incorrect. For information about x to be truly incomplete, there has to be at least the possibility that there are further true statements that could be made about x, i.e. statements that say that x is so, and where x is in fact so. No such possibility exists in this case. For example I can say

In 1998 a planet the size of Jupiter was miraculously created in the orbit between the Earth and Venus. It was made entirely of iron.

Which simply adds more falsity to what is already there. There is a great temptation to talk like this, and many serious and respectable people do. Perhaps it is enlightening, from the standpoint of human psychology, that they do. But perhaps it ought to be resisted.

Wednesday, May 28, 2008

Summa 94-103, Logic Museum

Questions 94-103 now available. There are some interesting observations on sexual reproduction in question 98. How would humans have reproduced in Paradise, without original sin, and in a state of innocence? Gregory of Nyssa said that the human race would have multiplied by some other means than the usual one. St Thomas objects that the usual method is natural to man by reason of his being an animal. And the 'corporeal members' must have had a natural use before sin. Thus the order of nature requires that there should be 'concurrence' of male and female for purposes of generation.

However, in the state of innocence there would have been no 'excessive concupiscence' (immoderata concupiscentia), when the lower members were entirely subject to reason. For which reason Augustine says (De Civ. Dei xiv, 26): "We must be far from supposing that offspring could not be begotten without concupiscence. All the bodily members would have been equally moved by the will, without ardent or wanton incentive, with calmness of soul and body."

Wednesday, May 21, 2008

The Theologian's Fallacy

So many blogs have started discussing Alan Rhoda’s ‘Theologian’s Fallacy’ that it’s time for me to get in on the act. In this case, merely as an index. Alan’s original post is here
with a follow up here. There are also:

Siris, plus follow-up [22 May] here.
Mormon metaphysics
Maverick philosopher
Declarations of the Dismissed
[added 22 May] WenatcheeTheHatchet

Saturday, May 17, 2008

Existence and assertion

Bill Vallicella's otherwise excellent discussion of 'thin' theories of existence in a series of posts at the Maverick Philosopher website has so far ignored the difference between theories where the existence of a singular referent is presupposed, and theories where it is asserted.

Consider 'Socrates is wise'. This affirms wisdom of Socrates. Does it also affirm existence of him? Does it then consist of two propositions, one of which affirms existence, the other of which affirms wisdom? Or does it consist of just one, that affirms wisdom without affirming existence? The latter view, sometimes called the 'Strawsonian' or 'presupposition' view, involves the following problem.

If Socrates does not exist, the negation of 'Socrates is wise', i.e. 'It is not the case that Socrates is wise' must be true. But if 'Socrates is wise' does not assert the existence of Socrates, neither does its negation (for a negation can deny no more than the corresponding affirmation affirmed). In which case the negation expresses exactly the same thing as if Socrates had existed, and wisdom was being denied of him, i.e. expresses exactly what 'Socrates is non-wise' expresses. But then it affirms non-wisdom of something, and so requires the existence of Socrates. But that cannot be, if Socrates does not exist.

But there is no such problem with the view that existence, as well as wisdom, is asserted. Then the negation of 'Socrates is wise' is the negation of a conjunction, and so is equivalent to the disjunction 'There is no such person as Socrates, or wisdom does not apply to Socrates'. There are different facts corresponding to Socrates' not existing, and Socrates existing but not having wisdom, and so the falsity of 'Socrates is wise' does not imply that a non-wise Socrates exists.

[edit] For an early defence of assertionism, see my translation of chapters 12 and 14 of the Ockham's Summa Logicae II here. For a later one that should be familiar to almost everyone, see Russell's Theory of Descriptions.