The anthropic principle is a common explanation offered -- contrary to claims by religionists -- for why the universe seems designed or "fine-tuned" in such a way that makes life possible. The anthropic principle states that any intelligent life-form able to contemplate the nature of the universe, the existence of God, etc. is inevitably going to find itself in a universe suited to life. (Any universe unsuited to life could not be observed by anyone.) Therefore, the observed nature of the universe, no matter how apparently "special," cannot be used as an argument for God.
The problem with the anthropic principle is that it accepts many of the religionists' arbitrary premises. For example, Objectivism would say that it is arbitrary (that is, disconnected from any evidence) to say that the universe could have been otherwise, or that multiple universes are possible. Such speculations are exercises in fantasy, not cognition. There are also some narrower, scientific claims in the religionists' argument that are based upon insufficient evidence, such as assertions that life would not be possible if various properties of the universe were different.
Objectivism demands that the religionists point to the evidence of reality to back up their claims, which they cannot. This strong position is weakened or obliterated if one goes down the road of trying to rationalistically deduce the consequences of arbitrary religious premises, and only later making a logical rebuttal. The truth is that there is no evidence that the universe could have been different. Stating this fact clearly, cuts off the religious "fine tuning" argument at its root.
answered Mar 15 '11 at 09:50
Andrew Dalton ♦