What do we know?

Actually, not much.

How do we know that we are not brains in vats? That we aren't software simulations in an advanced super-computer? That the entire universe of which we think we are a part wasn't created intact (complete with all our memories) last Thursday?

We don't. We can make a basic Cartesian assumption that "thinking" of some sort is going on somewhere, by the fact that we use thinking to make that assumption. But apart from that, we really don't know.

This is a scary thought. (But it is, at least, a thought.)

So where do we go from here? If we can't know anything, what's the basis of doing anything? Why go on, in the face of such uncertainty?

We have senses that seem to show us the world in a generally consistent way, so in the absence of certainty we can proceed in what appears to be a pragmatic manner. In the absence of certainty we can construct a worldview based on probability. We can live a life of induction, but we must first assume that induction works. Our senses may subsequently tell us that such an assumption appears to be consistent with reality as we perceive it. And so we build. Of such pragmatism is civilisation wrought — in sweat, in toil, in reasoned argument, in compassion. It is, we find, worth striving for.

For some people this isn't enough. They're unhappy with such uncertainty, and demand to be told in no uncertain terms, how things really are.

Such people will search for certainty, and believe they find it in religious scripture. They will seize upon the sacred text that purports to reveal in no uncertain terms the secrets of the universe. They will base their lives upon it, proclaiming its inerrancy. It must be inerrant — it's the truth they've been seeking, and if someone is so crass or unwise to question the inerrancy of scripture they'll explain, at tortuous length, why it contains not a single contradiction, and how it grounds their very existence.

But they're wrong. They're no better off than the rest of us — in fact they're worse off, having deluded themselves into thinking they are certain, in a world where certainty is impossible.

Absolutely wrong — more anti-naturalism in Dembski & Licona

As an exercise in misrepresentation Nancy Pearcey's contribution to Dembski & Licona's Evidence for God is hard to beat. In "How Darwinism Dumbs Us Down — Evolution and Postmodernism" she tries to make a case for naturalism being self-refuting. She doesn't refer to, or even mention Alvin Plantinga's Evolutionary Argument Against Naturalism, though she's writing about the same idea — but in a much dumbed-down manner lacking any focus. She claims that Darwinism undercuts rationality, without making a sufficient case for such a claim; her thesis in this respect suffers from the same flaw as Plantinga's: that although it's most likely true that evolution is responsible for our belief-forming mechanisms, our belief-forming mechanisms are not solely produced by evolution.

Critics of evolution (usually theists) often claim that "believers in evolution" maintain that Darwin's theory is responsible for absolutely everything. This straw man once again illustrates the theistic obsession with absolutes — Darwinism is responsible for everything, or it's responsible for nothing. (The theistic world is black and white: morality, for instance, is objective, absolute, unchanging and set in stone, or else it is an insubstantial figment of human imagination — nothing in between.) Pearcey's chapter provides examples early on, when she discusses the wider application of a naturalistic worldview:

At the foundation of these efforts, however, was a naturalistic approach to knowledge itself (epistemology). The logic went like this: If humans are products of Darwinian natural selection, that obviously includes the human brain–which in turn means all our beliefs and values are products of evolutionary forces: Ideas arise in the human brain by chance, just like Darwin's chance variations in nature; and the ones that stick around to become firm beliefs and convictions are those that give an advantage in the struggle for survival. This view of knowledge came to be called pragmatism (truth is what works) or instrumentalism (ideas are merely tools for survival). (p 82.)

This is wrong on several counts. Darwinism does not mean that "all our beliefs and values are products of evolutionary forces" — only some of them. Ideas do not "arise in the human brain by chance" — to suggest that they do in any significant quantity, is to suggest that the process of thinking is no more than a random synaptic cacophony — some of which might by chance be "useful". Clearly this is not so. As for pragmatism being "truth is what works", this is such a blatant oversimplification one hardly knows where to start with it. The entries on "pragmatism" in Wikipedia and the Stanford Encyclopedia of Philosophy might be worth a try. (Note that although Pearcey uses the phrase "natural selection" she seems confused as to how it operates. She appears to be suggesting that ideas can be inherited — in a kind of transcendental Lamarckism.)

Unfortunately the paragraph quoted above is only the fourth in Pearcey's chapter, and it effectively undermines and invalidates most of what follows it. It's an all or nothing argument, which, if you take it literally and find even one tiny flaw, the whole edifice crumbles. To use a favourite anti-naturalism ploy, it's self-refuting.

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