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.

When a male vole repeatedly mates with a female, a hormone called vasopressin is released in his brain. The vasopressin binds to receptors in a part of the brain called the nucleus accumbens, and the binding mediates a pleasurable feeling that becomes associated with that female. This locks in the monogamy, which is known as pair-bonding. If you block this hormone, the pair-bonding goes away.

We are nothing but the product of billions of years of molecules coming together and ratcheting up through natural selection, we are composed only of highways of fluids and chemicals sliding along roadways within billions of dancing cells, trillions of synaptic conversations hum in parallel, this vast egglike fabric of micron-thin circuitry runs algorithms undreamt of in modern science, and these neural programs give rise to our decision making, loves, desires, fears, and aspirations. That understanding would be a numinous experience, better than anything ever proposed in anyone's holy text.

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.

This is the hallmark of a robust biological system: political parties can perish in a tragic accident and the society will still run, sometimes with little more than a hiccup to the system. It may be that for every strange clinical case in which brain damage leads to a bizarre change in behavior or perception, there are hundreds of cases in which parts of the brain are damaged with no detectable clinical sign.

Visual cortex is fundamentally a machine whose job is to generate a model of the world.

There are three deaths. The first is when the body ceases to function. The second is when the body is consigned to the grave. The third is that moment, sometime in the future, when your name is spoken for the last time.