Your brain is built of cells called neurons and glia - hundreds of billions of them. Each one of these cells is as complicated as a city.

If you measure someone's brain and see very little activity during a task, it does not necessarily indicate that they're not trying - it more likely signifies that they have worked hard in the past to burn the programs into the circuitry. Consciousness is called in during the first phase of learning and is excluded from the game playing after it is deep in the system.

It is more parsimonious to assume that the sun goes around the Earth, that atoms at the smallest scale operate in accordance with the same rules that objects at larger scales follow, and that we perceive what is really out there. All of these positions were long defended by argument from parsimony, and they were all wrong.

If an epileptic seizure is focused in a particular sweet spot in the temporal lobe, a person won´t have motor seizures, but instead something more subtle. The effect is something like a cognitive seizure, marked by changes of personality, hyperreligiosity (an obsession with religion and feelings of religious certainity), hypergraphia (extensive writing on a subject, usually about religion), the false sense of an external presence, and, often, the hearing voices that are attributed to a god. Some fraction of history´s prophets, martyrs, and leaders appear to have had temporal lobe epilepsy.

When the brain activity is kindled in the right spot, people hear voices. If a physician prescribes an anti-epileptic medication, the seizures go away and the voices disappear. Our reality depends on what our biology is up to.

The deep secret of the brain is that not only the spinal cord but the entire central nervous system works this way: internally generated activity is modulated by sensory input. In this view, the difference between being awake and being asleep is merely that the data coming in from the eyes anchors the perception.

Some men may be genetically inclined to have and hold a single partner, while some may not. In the near future, young women who stay current with the scientific literature may demand genetic tests of their boyfriends to assess how likely they are to make faithful husbands.