Are the sciences that might explain the human mind—neuroscience, psychology, psychiatry’still in their infancy? Or have we reached some fundamental scientific limit to our understanding of the human brain and how it works? More essentially, do we really know any hard scientific truths about the brain and mind” or do we just hold a series of shifting beliefs suited to the age in which we live? Journalist Horgan (previously a senior writer at Scientific American) looked at some similar ground in The End of Science (not reviewed), where he argued that for particle physics, cosmology, and evolutionary biology, scientists may have reached the end of what there is to discover. On the other hand, he postulates here, the scientific disciplines attempting to explain the human mind have hardly made a start. We can’t explain the most complex question—consciousness; we don’t know “what processes in the brain allow us to see, hear, learn, remember, reason, emote, decide, act,” nor why ’so many of us [are] afflicted with mental disorders such as depression and schizophrenia.” Nor do we know how effective treatments are for these disorders. Horgan has many more questions than answers, but on some points he’s quite clear, and his arguments are instinctively appealing. “Theories of human nature never really die, they just go in and out of fashion.” Hence “phrenology is reincarnated as cognitive modularism. Sociobiology mutates into evolutionary psychology,” and so on. Horgan pays particular attention to psychiatric issues, first and foremost its treatment modalities. His feeling is that current treatments are not “truer or better” than past haphazard attempts to help the mentally ill—they’re just different, for our era. Horgan doesn’t come across as bashing the relevant professions or rabble-rousing for the fun of it; in fact, he lists in order the help he would seek if affected by a serious depression. Rather, he raises some tough, provocative questions. Thought-provoking, and an overall useful exercise.