You Don't Know Anything Book

Gary Marcus gives us a thoroughly readable and enjoyable survey of what is known and surmised about how our genetics affects our brain, and what it does. The illustrations are pertinent, the mix of technical terms and memorable anecdotes is just about right, and a wide range of great thinkers (Pinker and Dawkins, Crick and Mendel) are called upon to help illustrate the problems and their purported solutions.

But, does it really give us anything we didn't already have, this book?

In some sense, the answer must be no. We already knew that genetics controls some aspects of our thinking, but not all, and that which it does control still interacts with our environment. We already knew that some of this is present even in the lowly fruit fly, without any evidence that fruit flies think as we do, because the same gene can code for multiple different affects in different species or different parts of the body (e.g. brain and not-brain), This is not, in other words, a "big idea" book.

The field of genetics and neurology are slowly colliding, like two galaxies that pass through each other. There are a lot of things left to be discovered here, including a lot of discoveries with the potential to cause major changes to fields like education, criminal justice, political science, and economics.

This is because most of our thinking happens by analogy, and most of our analogies in this area are wrong. Not just wrong in the way all analogies are approximations of the truth, either. We think of DNA as a blueprint, but it's more like a recipe; rarely is there a one-to-one correspondence between the letters of a recipe and the parts of a dinner entree. We think of the brain as a computer, but it's more like a muscle (use it or lose it). We think of memory as a videotape, but it's more like the script to a play (you see Hamlet's outfit, but it is described in the text in only the most general way, and that of the other characters not at all, notwithstanding which they will usually appear in your memory wearing something).

In most areas of science, popular understanding is not just behind that of researchers (an inevitable state of affairs, almost by definition of "researcher"), it is also falling further and further behind. Our criminal justice system still relies upon eyewitness testimony more than any other form of evidence, even though it has long since been demonstrated to be far less reliable than every jury supposes. Our economic systems suppose that the brain is either perfectly rational, or in need of protection from its own errors in judgement (by brains with superior judgement, one supposes), but none give much attention to how to make the environment one in which our brains would work best.

There are those, like proponents of Intelligent Design, who are more or less openly opposed to science. I do not fear their focused enmity so much as I fear the apathy of the masses, who are not so much opposed to science as oblivious to it. The greatest threat to science, and the society that uses it, is not religious zealotry, which is a threat Science has lived with, and prospered in spite of, since its earliest days. No, the greatest threat to science is a society which says, 'no thanks, I'm full'. If we freeze our understanding of how the world works at somewhere around the mid-twentieth century, the ever-growing distance between scientists and the population they live among cannot but result in an ever-growing resentment between the two.

It is into this situation that a book such as this one by Gary Marcus steps. It is not, as I said, a "big idea" book. It puts forward no grand new schemes for ordering our thoughts. We will not see quotations of Marcus' text in decades to come.

What Marcus does, and does well, is survey again for us what is known, and how we know it, for those who care about the impact of genetics on our concept of free will, but are not certain that they understand what is known about it. It approaches each problem from several angles: presenting of data, diagram, pithy anecdote, thought experiment. Whichever one works best for the reader to digest, he provides it. Marcus' book is what textbooks should be like, but almost never are. It is a book which makes us slightly less ignorant about our own true natures, a subject about which nearly every human living could use some instruction. Read it if you care.