In every age, the way the brain works has been likened to the way that advanced machinery of the time worked. (Jaynes make a similar point about consciousness.)

• When aqueducts and pipes to move water were the exciting new thing, much was attributed to the fluid filled parts of the brain as the hydraulic basis of its functioning.
• Later, in the industrial age, mechanical machines were developed and in turn became a basis for trying to understand the brain as a wondrous machine.
• With the advent of telephone communications, the brain was likened to a giant, interconnected switchboard routing and moving electrical messages.

Thus, it should come as no surprise that in the latter half of 20^th century the brain becomes likened to a computer.

• It's important to spend a moment with the phrase "likened to." All to often it is easy to confuse our ideas of analogy and homology.
• Do we mean that we can conceptualize brain function using terms derived--by analogy--from computer science, or that indeed the brain is a computer--homology--that happens to be made up of a carbon based chemistry rather than a silicon based one?

An approach based on homology--the brain is just like a computer--can easily get turned around and thus we find the question posed: If a computer complex enough is built will it have consciousness in the same way a human does?

• For now I do not mean to engage in the argument of whether consciousness exists. In fact, I want to turn the argument around and explore what attributing consciousness to a computer might tell us about the parameters of consciousness.
• Also, I take the opening sentence of this section as a warning not to fall prey to the prideful assumption that our technology has now finally--really this time we've got it right--caught up to our intrinsic nature. If the brain is a computer, much will need to be done to prove that fact.
• Similarly, the fact that turning the argument around leads to attributing consciousness to a complex enough computer causes some to flatly assert the impossibility of such a thing, as thus simply deny the brain is a kind of computer.

The remainder of this article addresses the validity of likening brain to computer based on rigorous and fundamental arguments, and not simply on analogy.