Like any position in philosophy, it’s a matter of weighing pros and cons really. Those reductionists will have to pay a hefty price for sticking with naive reductionism. For example, they’d have a hard time arguing against dualism from a point of parsimony or simplicity if they accept a world where something as daily and mundane as pain is identified as an infinity of conjuct physical facts. How is their explanatory power more robust in this sense than a nonphysicalist account?

I haven’t thought of this in a while (this post is form 2006), but I believe reductionism itself might be inconsistent with this sort of “infinite regress” of facts-to-identity. Obviously, there’s approaches which don’t adhere to this sort of naive identity statement in the first place, but the main issue is accepting that contrary to common misconception, the scientific method itself is moving towards accepting explanatory models which include macroscopic events which are irreducible to microscopic events. We don’t have an explanation of emergence yet, but denying it completely is looking more and more an ad-hocist position, and not something which fits well with our understanding of physics.