Galileo and the Altar Lamp Pendulum

IN 1583 Galileo Galilei (1564–1642), a youth of nineteen attending prayers in the baptistery of the Cathedral of Pisa, was, according to tradition, distracted by the swinging of the altar lamp. No matter how wide the swing of the lamp, it seemed that the time it took the lamp to move from one end to the other was the same. Of course Galileo had no watch, but he checked the intervals of the swing by his own pulse. This curious everyday puzzle, he said, enticed him away from the study of medi...

 Conservation Tasks and Reason

Piaget had his own way of assessing brain maturation during this period, using his now-famous "conservation" tasks, try this one out on your tour-to-eight-year-old: fill two identical short, squat glasses with equal volumes of water, and ask your child, "Do the two glasses contain the same amount of water, or does one have more?" Now, pour all the water from one of these 'lasses into a tall, narrow glass, and ask your child the same question. Four-year-olds almost invariably say that the ta...

 Genes versus Hormones in Homosexuality

It is clear, however, that the cause of homosexuality lies in some unusual balance of hormonal influence in the womb but not later on, a fact that further supports the idea that the mentality of sexual preference is affected by prenatal sex hormones. This is not incompatible with the growing evidence that homosexuality is genetically determined. The "gay gene" that I will discuss in the ext chapter is widely expected to turn out to be a series of genes that affect the sensitivity of certain t...