A digital computing machine can accomplish in a day a body of work that would take the full efforts of a team of computers for a year, and it will accomplish this work with a minimum of blots and blunders. On the other hand, the human being has certain non-negligible advantages. Apart from the fact that any sensible man would consider the purposes of man as paramount in the relations between man and the machine, the machine is far less complicated than man and has far less scope in the variety of its actions. If we consider the neuron of the gray matter of the brain as of the order 1/1,000,000 of a cubic millimeter, and the smallest transistor obtainable at present as of the order of a cubic millimeter, we shall not have judged the situation too unfavorably from the point of view of the advantage of the neuron in the matter of smaller bulk. If the white matter of the brain is considered equivalent to the wiring of a computer circuit, and if we take each neuron as the functional equivalent of a transistor, the computer equivalent to a brain should occupy a sphere of something like thirty feet in diameter. Actually, it would be impossible to construct a computer with anything like the relative closeness of the texture of the brain, and any computer with powers comparable with the brain would have to occupy a fair-sized office building, if not a skyscraper. It is hard to believe that, as compared with existing computing machines, the brain does not have some advantages corresponding to its enormous operational size, which is incomparably greater than what we might expect of its physical size.