We do many things by doing something else. You might move across the room by walking and walk by moving your legs. But do you move your legs by doing something else? You might think, yes: by sending nerve impulses from your brain. And maybe you do that by sending around other such things in your brain? But are “you” really doing those things that happen in parts of you?
The priest and philosopher Nicolas Malebranche argued that no-one can really do anything themselves because in order to do something, you need to know how to do it — and we don’t know how to cause all that neural stuff that needs to happen for our bodies to do anything. (He thought God is really the one who does everything.) This isn’t a good argument. To know how to do something must mean knowing how to do that something by doing other things (eg. how to move your hands and fingers while playing the piano). So if you must always know how to do everything, then you must know how to do the things by which you do that other thing: how to make your fingers move, and then probably how to send those neural signals, and then how to do whatever you do to do that; it’s an infinite regression. To make the regression stop, there must be some things we just can do, so that we can do more complex things by doing those things. Continue reading