> Yeah I get that, but if we're inventing magic infinite computers, why not invent magic halting algorithms? Do you object to doing geometry because it involve

> Yeah I get that, but if we're inventing magic infinite computers, why not invent magic halting algorithms? Do you object to doing geometry because it involves a magic infinite plane? The point is that by studying the behaviour of this simple model we can learn useful things. > This paragraph is essentially saying this - if we had magic computers then we could magic things we them, but we don't so we can't. If you knew what a program would do on a magic computer, you could do very interesting things. The point isn't to have an actual magic computer.