Monday, May 05, 2008

The Problem With Possibility and Evidence

So much for posting once a day this year! However, I would at least beg your indulgence for this most recent drought - my home computer has crashed, and with it, a lot of the posts in preparation!

I must admit that I have been pretty lucky over the years with digital storage, but you only need one crash, and 8 years of thoughts and memories - poof!

Anyway, I had mentioned in a comment on the Varieties of Unreligious Experience the following:

In reading your post, I couldn’t help but think of the “anybody but Shakespeare” movement – Christ, even Derek Jabobi doesn’t think Shakespeare wrote his plays! So your point about intelligent people falling for these kinds of things is both well-taken and well-founded.

But when it comes down to it, doesn’t this all revolve around the fact that one can say, without contradiction, that the 2nd Earl of Essex really wrote Shakespeare’s plays, despite his 1601 beheading, that the evidence is there, you just have to look at it so, with a little charity in your thoughts as you read my outlandish thoughts? That nothing rules out the possibility of this logically?

I had prepared a post on this, but it's gone, so I am instead going to present something that, in what I hope is a nice Wittgensteinian vein, shows what I mean here instead of argue for it!

A Break in the Garden

Two philosophers (A and B) have just finished a conversation about a nearby tree. Two non-philosophers (A and B), walking nearby, decide to join the philosophers.

Instead of continuing their discussion about the tree the philosophers had been so interested in, the pairs embark on a conversation about the possibility of rain tomorrow.

Each conversation begins with a sentence A, “It is possible that it will rain tomorrow,” and is answered with a reply B, “How do you know?”

So Non-philosopher A’s reply is likely something along the lines of “I checked the weather,” or, “I saw a forecast on television.” One could also expect talk using folk knowledge, like the appearance of a clear sky at dusk. Possibility here is founded in some kind of sensual evidence.

Moreover, Non-philosopher B would likely accept this explanation, and perhaps try to remember not to leave home without an umbrella tomorrow. In other words, Non-philosopher B would probably act on philosopher A’s knowledge of tomorrow’s weather conditions.

Now contrast this with what happens when the philosophers and non-philosophers next meet.

The following day, the philosophers are again sitting near the same tree, and the non-philosophers again sit down next to them. This time, Non-philosopher B turns to philosopher A, and smiles. Philosopher A says , “It is possible that it will rain tomorrow.” Non-philosopher B says “How do you know?” Philosopher A replies, “because it is possible for it to rain tomorrow.”

Non-philosopher B is somewhat perplexed here. He says “what do you mean?” The philosopher replies, “you accept that it rains here, right? Then rain is possible tomorrow, isn't it? On cannot rule out it raining tomorrow.” Non-philosopher B, feeling perhaps a bit misunderstood, nevertheless accepts the philosopher’s answer.

I hope the distinction between the two conversations is clear, as it is very hard to express this difference in any way except by reminding oneself of the times one has said or was confronted with this kind of use of the word “possible”, and perhaps imagining the philosopher probably stressing the word "possible" as he says it.

For the non-philosophers, “because it is possible for it to rain tomorrow” expresses a kind of empirical possibility, whereas the philosopher is concerned with something I would call conceptual possibility.

The philosopher has no need to check the weather, and there is nothing that lends credence to this assertion except that one can say that rain is possible tomorrow, because it rains on earth, which is an empirical fact, but there's no empiricism in the philosopher's observation, is there?

The big problem, howevr, is that what the philosopher is saying isn't nonsense. This is a perfectly reasonable way to use “It is possible that it will rain tomorrow.”, isn't it?

Many people, smart people, speak of things in this conceptual way all the time when speculating about how things might have been or might be. Worse yet, in the instance of the Shakespeare-as-Bacon camp, they appear to have evidence for their arguments!

But isn't what makes the arguments possible in these kinds of cases, not the evidence, but the possibility of evidence, the possibility of being wrong, the possibility of there being no certain knowledge, the possibility that the Templars never disbanded, etc?

See how I have to use that philosophical possibility here to try to dispel the conceptual possibility both cranks and fine scholars use to justify their claims?

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