Because we do not understand the brain very well we are constantly tempted to use the latest technology as a model for trying to understand it. In my childhood we were always assured that the brain was a telephone switchboard...Sherrington, the great British neuroscientist, thought the brain worked like a telegraph system. Freud often compared the brain to hydraulic and electromagnetic systems. Leibniz compared it to a mill...At present, obviously, the metaphor is the digital computer.

You can't *discover* that the brain is a digital computer. You can only *interpret* the brain as a digital computer.

My car and my adding machine understand nothing: they are not in that line of business

There is no success or failure in Nature.

Many people mistakenly suppose that the essence of consciousness is that of a control mechanism

I will argue that in the literal sense the programmed computer understands what the car and the adding machine understand, namely, exactly nothing.

We do not live in several different, or even two different, worlds, a mental world and a physical world, a scientific world and a world of common sense. Rather, there is just one world; it is the world we all live in, and we need to account for how we exist as part of it.