Résumé: Gerald Edelman grieves over the "divorce" science and the humanities have experienced. Since there is no final decree in the proceedings, he wants to heal the breach. He has a mechanism to further the reconciliation - something he calls "Second Nature". That "Second" is the human's brain's extensive capabilities - capabilities that exceed what we see in the rest of Nature. With his long career in brain science and as a scholar well versed in the evolutionary background that makes us human, he may have an appropriate answer. In this book, he makes an excellent case for why the divorce need not be permanent. It's offered as a conciliatory gesture under the banner of his theory of "Neural Darwinism".

The label implies the obvious - our brains - hence, our minds - hence our "conscicousness" is the product of natural selection. It's not something separate from the real world in any way. Edelman, like all philosophers today, must face the still unfinished task of eliminating Descartes' "dualism" from consideration. "Dualism" effectively denies our evolutionary heritage. What is that heritage? Edelman enquires, and offers us his view of it.

Humans are distinct from the rest of the animal kingdom in one important way - our version of consciousness. As our brain developed, it created a unique form of neural pathways. Not only is the neural net highly complex - in a single human brain, the potential connectivity "far exceeds the number of elementary particles in the universe" - the methods of connecting are unique. Our brain, which spends far more effort viewing itself and the rest of the body than it does dealing with incoming or outgoing signals, uses a host of internal feedback loops ["reentrant" processing] to do its job. These reentrant signals are reinforced by areas Edelman calls "degenerate". Degeneracy doesn't imply deterioration, but instead is a kind of redundancy - many areas in the brain handle the same or similar tasks. With this brain structure emerging in early humans, selection could favour certain brains and pass their patterns down the generations. Habits once erratic and highly individual, ultimately became the social norm - many individuals shared the trait. Language, of course, with syntax and vocabulary, enhanced those inherited abilities. However, Edelman is dismissive of the concept of a "language module". Instead, he feels that communication reinforced traits already present, enhancing social interactions and forging bonds. Those bonds further contributed to behaviour factors literature describes and philosophy analyses.

Much of Edelman's presentation is reminiscent of Edward O. Wilson's call for "Consilience" in the book of that name published a few years ago. Edelman, however, in a bizarre designation, calls Wilson's proposal "reductionist". One can only tremble at the thought of Wilson's reaction. Richard Dawkins' "memes" are also dismissed as almost unworthy of notice. The author's grand, comprehensive view of the brain rejects anything "mechanistic". Yet, in what seems to be unconscious irony, Edelman concludes the book with a discussion of robots. Recently, some scholars have proposed the idea of an unconscious robot. It may look, walk and talk like a human, but lacks "consciousness" under most definitions. Edelman's team has, however, constructed a series of devices with extraordinary capabilities. Aptly named "Darwin", they've constructed several versions. These devices are highly mobile, and possess numerous input devices that "hear", "see" and "feel". Instead of programming them to seek or avoid objects or obstacles, the Darwins are set loose to wander and examine. When they perform approved acts, they are given verbal approval. This leads to "better" behaviour in future excursions. These robots "learn" how to live. Clearly, this is rich fare for the humanities to savour. As is the entire book. [stephen a. haines - Ottawa, Canada]