Logic and Faith

Bill Vallicella, the Maverick Philosopher, comments here on Sam Harris’s book The End of Faith: Religion, Terror, and the Future of Reason. I haven’t read the book, so I must be careful about what I say here, but from the excerpts quoted, and the interview given by Harris at Amazon, he (Harris) appears to be staking out a position that, with unintended irony, is the product of his own faith. The most telling example of this is something he said in this interview:

‘Faith’ is a false belief in unjustified convictions.

Let’s examine this. What Harris is saying is, in other words: believe nothing without evidence. Logic and reason are what we must rely on.

But what is logic? Why its appeal?

I think nobody would deny the existence of intuitive faculties in all of us. We all act on hunches from time to time, or pick a course of action because it just “feels right”. When we have a tough decision to make, we are told to “trust our gut”. Most people would say, though, that this is very different from – in fact, the exact opposite of – using reason or logic. But to say this is to overlook the fact that all logic is at its root founded on faith.

The beauty and utility of logic are due to the way it somehow codifies not only human thought, but also seems in a mysterious way to mirror the way the truths of the world link together. It has been pointed out that this is not, perhaps, such a surprising coincidence – we perceive the “truths” of the world through the filter of the human mind, so any process that models the connection of human thoughts, as logic does, will also represent the connections between the truths we are able to perceive.

There is enough that is common to the reasoning of most human minds that it has been possible to create an abstract method – logic – for sequentially connecting truths. The key is that logic is public – once we agree on the rules of logic, all we need is some suitable premises to start with, and off we go, proving truth after truth, with no end in sight. The problem, though, is that once we get far enough along in pursuit of some distant or unforeseeable end, it is very easy to forget where we started. And the beginning of every logical chain is an act of faith: some unproven axiom, some set of postulates that were chosen because they simply felt true. There’s no getting around this, because logical inference can only draw on what is previously given, either as an axiom or a theorem already proved. To demand that every step in a logical chain depends on an earlier logical proof leads, of course, to an infinite regress.

Once we have axioms we are all happy with, though, there’s no stopping us. The modern Western experiment has been going along for a good long while now, and the results have been spectacular. The belief is widely held (whether it is true or not) among rational secularists that there is in principle no limit to the scientific exploration of the World; that the web of logical inference we have built will continue to expand until all the truth of the world is within its compass. It is easy to see why this view is popular – look at what we’ve done so far!

But there is no guarantee of this. There is necessarily a connection between the links in a logical chain. If wish to bring all of the truths in the World into a single logical mesh, then there must be no isolated regions. It is quite possible, though, that for any set of axioms, there is a contiguous set of truths that are logically accessible, but others that are not. If logic is a car, and your axioms start you off in Pittsburgh, you are going to be able to see a lot of interesting places, but you will never get to Paris.

So a great deal depends on the axioms we choose, and unfortunately, due to the very nature of logic, we cannot prove their validity. Axioms must be accepted, painful though it may be, on faith. And faith is necessarily not public. If I believe something on faith, I can try to convince you of it – by emotional force, by metaphor or allegory, by saintly example – but I can’t compel your agreement the way I can with logic – assuming we agree on the rules of logic. Faith is private.

Two very popular axioms:

“God Exists.”
“There is no God.”

You can see a lot of interesting countryside from each of these starting points. And you are going to miss a lot, too.

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One Comment

  1. Anonymous says

    Bill Vallicella responds here.

    Posted September 1, 2005 at 11:56 pm | Permalink