Z. M. Davis:
Hard to say. I don't really see the difference between "time is 'just' a coördinate in 3+1-dimensional spacetime" and "time really doesn't exist." ... something still has to account for our memories, and clocks, and the apparent changes in what we perceive: for things to be otherwise would be a violation of Egan's Law.
That something is the Second Law of Thermodynamics. The only arrow of time which is not explained by thermodynamics ( + quantum decoherence) + anthropic principle is a CP violation in certain subatomic interactions. Hopefully Eliezer's next post will explain this more clearly.
More details of my views on the subject can be found here.
With the rise of "open source biology" in the coming decades, you'll probably be able to sequence your own non-coding DNA and create a pack of customized cockroaches. Here are your Nietzschean uebermensch: they'll share approx. 98% of your genome and do a fine job of maximizing your reproductive fitness.
Only in humans does it make predictive sense to talk about intent, capability, and inclination, and the wide gap between these kinds of perceived "properties" of fellow socially interacting humans, and the generally much simpler properties seen in inanimate objects and animals, leads the brain to allocate them to widely separated groups of buckets. It is this perceived separation in mental thing-space that leads to the the a free-will boundary being drawn around the cluster of socially interacting humans.
careful there. animistic beliefs are quite widespread in tribal societies, so the notion that the brain allocates two entirely distinct clusters to humans and animals vs. inanimate objects is quite suspect.
But if you throw out causality along with time, it is hard to see how a low-entropy terminal condition and high-entropy initial condition could produce the same pattern of similar and dissimilar regions.
Aren't you assuming an expanding universe here? Some physicists speculate that if the universe were to contract in a Big Crunch, quantum decoherence would reverse and macroscopic entropy would decrease as highly correlated quantum fluctuations would be erased by destructive interference. The end effect is that the thermodynamic arrow of time is reversed and such a situation becomes indistinguishable from an expanding universe with increasing entropy. I'm not sure if this is a widely accepted view.