bigideas

There’s a touch of quis custodiet ipsos custodes over at Mark F. Sharlow’s web site, whose purpose is to skeptically debunk common arguments put forward by self-styled skeptics.

There are a lot of names for what’s becoming an increasingly fashionable attitude: secularism, humanism, rationalism, atheism, skepticism. These terms all name different things, of course, and many people take a nuanced view, perhaps subscribing to some and rejecting others. But there are people who don’t really appreciate the differences and haven’t thought too deeply about what each of these various views entails. These are the people Sharlow is going after.

Several of Sharlow’s criticisms of naive arguments put forward by “skeptics” come down to pointing out the incompatibility between rationalism and empiricism, both of which are claimed simultaneously by some.

Roughly speaking, empiricists consider knowledge to consist of information you gather from the world in the form of evidence. Traditional science is empirical, including the things like physics, biology and chemistry that many skeptics present as their gold standard for knowledge and even “truth”.

Now, empiricists are, like you and I, finite beings, so they can only observe a finite amount of evidence. Yet the conclusions they draw are “laws” that apply more widely than the specific cases that were observed; that’s what makes science useful, but at the same time it means all epiricists must make leaps of faith about the nature of the universe.

Although the resulting assumptions are widely held and rarely questioned, they cannot be justified except empirically — that is, by reference to the effectiveness of science and the successes of technology. This is why scientific “truths” always have to be considered contingent.

A rationalist, on the other hand, insists that beliefs must be justifiable by reason. Mathematics is a rationalist’s discipline; its justifications are logical proofs rather than evidence. Rationalists cannot make the leaps of faith required by the empiricist; to move from the specific to the general is, for the rationalist, a fallacy; an argument that uses it should be discarded. But it’s the characteristic gesture of empiricism, without which science can’t get started.

The difference here is between two styles of argumentation; deductive and inductive. Rationalism uses deduction; empiricism uses induction. You can’t use both as the basis for your way of life, or even your theory of truth, because they’re fundamentally in contradiction. One of the two must take precedence, and anyone who claims to be both an empiricist and a rationalist has to meet this problem head-on.