"The evolutionary process has a finite amount of time in which to work (because of eventual heat death), while Boltzmann brains have an infinite amount of time to appear in any given universe (that doesn't recollapse), and in the environment that birthed those universes. The ordinary observers created by natural selection simply drop out of consideration, being overwhelmed by infinitely more Boltzmann Brains."I wrote back to my friend with a paraphrase of this argument. However, for some reason I still think there was more to my objection, but I don't have enough time to figure that out right now.
Anyways, the guy who wrote the article I am objecting to is an astrophysicist; so given my lack of expertise in the area, I should tread lightly. However, Don N. Page observes something similar to my argument in one of his articles so there's possibility that I'm not insane: "Theories in which spacetime can last too long seem in danger of producing too many Boltzmann brains" (Observational Selection Effects in Quantum Cosmology)
And I certainly must disagree with what the post implies in this statement:
"Although there have been a number of scientific papers in the last couple of years on this topic, none of them were written, apparently, by anyone with a very deep understanding of biology."Physicists certainly don't need to have a "deep" understanding of biology to know that evolution happened, and to understand entropy and thermodynamics better than biologists.
In fact, there may be reasons for not even considering evolution (in our estimation of the ratio between Boltzmann brains and ordinary observers) because there is no reason that evolution should produce a conscious organism. Evolution only selects for behavior, and not consciousness, and there is no way (that I am aware of) to pose a concrete relation between the two. This may sound a little nuts, but if you look at the Chinese Room argument (here at IEP) or (here at SEP) you may understand. This is especially true of a consciousness that would be aware of what is actually going on outside of itself, and not just the strange characters (if you will) that it is manipulating.
All we know (assuming our senses are trustworthy) is that we have evolved, and are conscious (I am rather, I don't know about you), and if materialism is correct then consciousness is a result material interactions that, given enough time, can be replicated by random fluctuations, and who knows what else. However, we can go further and say that because of the principle of mediocrity we can't even say that our consciousness is the most likely form, or that other material interactions can't produce similar effects.
We can't say for sure that a radioactive rock hasn't had a conscious thought at some point in its life/half-life. How would it tell us if it did? Have we every been able to put ourselves in the "shoes" of a whirlpool or a dust storm? Is the mud possibly more likely to be a conscious observer than the plants or worms it turns into? or even us? These are questions that cannot be answered from a materialistic perspective. Evolution may concentrate what we subjectively label as "complexity" but it doesn't guarantee that this form of complexity is more likely to result in consciousness.