The Brain Revolution
Your brain is a mass of cells inside your skull and weighs around 1.4 kilograms, or 3 pounds.
Common sense insists that your mind, with all its amazing powers of thinking and feeling, cannot just
be your brain. The contrary belief that minds are souls is firmly held by the large majority of people
who belong to theistic religions, and by many philosophers since Plato and Descartes. They allow
that the mind may be closely associated with the body and especially with the brain, but insist that
mind and brain are not the same because they have different properties. Your brain has mass, consists
of matter and energy, and ceases to function when you die; whereas your soul weighs nothing, is not
subject to physical laws, and survives your death. Most people today are dualists, believing that a
person consists of both a spiritual mind and a physical body.
In contrast, most psychologists and neuroscientists are materialists and believe that minds are
brains: the mind is what the brain does. General acceptance of this view would amount to the most
radical conceptual revolution in the history of human thinking. Previously, the two most sweeping
scientific revolutions were Copernicus's rejection of Ptolemy's view that the earth is the center of the
universe, and Darwin's rejection of the religious view that humans were specially created by God.
According to modern astronomy, the earth is just another planet circling the sun, which is just one of
billions of stars in billions of galaxies. According to Darwin, humans are just another biological
species evolved through natural selection. The Brain Revolution now in progress is even more
threatening to humans' natural desire to think of ourselves as special, for it implies that our treasured
thoughts and feelings are just another biological process. Unsurprisingly, even some nonreligious
thinkers find disturbing the view that minds are brains, despite mounting evidence for such
identification. Not only immortality but also highly compelling doctrines of free will and moral
responsibility have been tied to the idea of minds as souls. The lure of dualism is powerful.