Materialism requires reductionism; therefore the failure of reductionism requires an alternative to materialism. My aim is not so much to argue against reductionism as to investigate the consequences of rejecting it—to present the problem rather than to propose a solution. Materialist naturalism leads to reductionist ambitions because it seems unacceptable to deny the reality of all those familiar things that are not at first glance physical. But if no plausible reduction is available, and if denying reality to the mental continues to be unacceptable, that suggests that the original premise, materialist naturalism, is false, and not just around the edges.

Thomas Nagel, from Mind and Cosmos.

This book is extremely controversial among those who haven’t read it. Yes, at places it fails to understand how complexity can arise from simple processes iterated over time. That said, Nagel is surely correct that naïve reductionist accounts of the world that deny reality to things that are self-evidently real must be false. I have more reason to know that qualia are real than I have to know any other thing–they are the most certain and real feature of the world. It is necessary to explain things like this and not just explain them away.