Very good article by Gary Marcus in the Boston Review:
In the nine-month dash from conception to birth—the flurry of dividing, specializing, and migrating cells that scientists call embryogenesis—organs such as the heart and kidney unfold in a series of ever more mature stages. In contrast to a 17th century theory known as preformationism, the organs of the body cannot be found preformed in miniature in a fertilized egg; at the moment of conception there is neither a tiny heart nor a tiny brain. Instead, the fertilized egg contains information: the three billion nucleotides of DNA that make up the human genome. That information, copied into the nucleus of every newly formed cell, guides the gradual but powerful process of successive approximation that shapes each of the body’s organs. The heart, for example, begins as a simple sheet of cell that gradually folds over to form a tube; the tube sprouts bulges, the bulges sprout further bulges, and every day the growing heart looks a bit more like an adult heart.
Even before the dawn of the modern genetic era, biologists understood that something similar was happening in the development of the brain—that the organ of thought and language was formed in much the same way as the rest of the body. The brain, too, develops in the first instance from a simple sheet of cells that gradually curls up into a tube that sprouts bulges, which over time differentiate into ever more complex shapes. Yet 2,000 years of thinking of the mind as independent from the body kept people from appreciating the significance of this seemingly obvious point.
Rest of Marcus’s article here.
And here you will find a number of reviews of Gary Marcus’s book The Birth of the Brain: How a Tiny Number of Genes Creates the Complexities of Human Thought, about which Steven Pinker writes, “A brilliantly original book that is a contribution both to popularizing science and to science itself.”
