But even more importantly: what in the world could make someone so hubristic as to assert, with absolutely no evidence, that humans, a single species on a single planet that happened to arise as an accident of evolution, have nonetheless capable of knowing the whole of reality?!? What could possibly justify the claim that the human animal is somehow capable of painting a comprehensive picture of the universe? Why should we suppose--again, with no argument or evidence--that reality in its entirety must conform to the concepts and theories of human scientists?
I've taken my time coming up with a response, but while blog threads go cold very quickly there is no statute of limitations on philosophical arguments. I want to comment on a few things in the quote above because it casts into very clear language typical objections to science in general: overreaching and hubris.
Overreaching here argues that because our scientific knowledge is nowhere near complete, we cannot say anything about the ultimate shape of reality. It's clear from even a cursory glimpse at the history of science that knowledge derived from science has never given a comprehensive or even wholly accurate picture of the universe. Scientific knowledge evolves. Every experiment answers one question and poses ten more; every theory begs insistently to be falsified; every law lays out a program for its own destruction. Cast by some as weaknesses, these in fact are the great strength of the scientific method -- it can bend the face of evidence. Science, more than any other method of inquiry, has an open mind. The gaps in scientific knowledge, however, say nothing about materialism. While there are many things we don't know, we know a great deal about the shape of the puzzle pieces that will fill in the gaps. New knowledge, however revolutionary, is unlikely to throw into question the core understanding that lies at the backbone of science. Even though the physics of 1915, for example, looked very different from that of 1885, it was ultimately still materialistic. The curvature of space-time and the particle-wave duality -- while novel -- were entirely effable, measurable, and objective. Any future extensions of scientific knowledge will most likely be equally material in nature.
Hubris is also a common charge leveled against science. But it is not arrogant to state with confidence that which we know to be true. If I say that it's impossible to separate a power higher than the second into two like powers, that is not hubris but irrefutable truth hard won by centuries of mathematical toil. Likewise, if we say with confidence that humanity arose by a blind process of variation and natural selection -- 'an accident of evolution' as Dadahead acknowledges above -- that is not hubris but an accurate explanation of our own origins that we are privileged to know by virtue of painstaking scientific research spiced by inspired insight. If we state these truths proudly it's because of all the careful effort that first went into justifying them.
Together these amount to a charge of "scientism," a multi-faceted epithet which in this case refers to the belief that science is the only method which can arrive at truth. Most agree that science is the best method ever employed for determining truths about the physical universe. If you also accept that the universe consists of nothing but the physical, then science is the best method for determining truths about the universe, period. This sounds like hubris to some. But they have failed to grasp the profoundly deep humility of science: that all truths are provisional. Everything we think we understand, all the mathematical laws, all the elaborate theories, everything is subject to skepticism and revision. Even the scientific method itself. If a new approach could be shown to have a better claim to accuracy, the old methods of science would humbly step aside.
Even the philosophical underpinnings of science are open to investigation. Science is said to be grounded in "methodological naturalism," a tentative form of materialism that acts as a metaphysical foundation upon which other scientific results can rest. But it is not, at least in principle, axiomatic or dogmatic. Naturalism, like all scientific theories, is justified by abduction, because it fits the data better than other explanations. In essence, it's true because it works. If we imagine that this most basic theory is itself held provisionally and could be revised, what kind of evidence could be presented that would falsify it, even in part?
But we can do better than wait for evidence that will never come. While even well-supported theories like Evolution remain tentative and provisional scientific truths, materialism is much stronger. Materialism is true analytically. The argument goes like this:
1. existence is objective
2. objectivity requires evidence
3. evidence is material
4. therefore, existence is material
This probably looks very weak on the face of it, something you could smash easily with a well-chosen aphorism. I will endeavor in future posts to put flesh on this skeletal syllogism. While not strictly formal, hopefully when the terms are defined and the loopholes are closed this argument will help persuade you, like me, of the necessity of materialism.