And actually Boole is only dealing with two distinguishable states. Any two distinguishable physical states can be used to define binary 1 and 0. But in general, any N distinguishable states can be used to form an algebra. N=2 is just the simplest, most elegant, and what most real computers are based on. I've heard rumors that an N=3 computer exists, aka 'ternary' (EDITed) but I have my doubts. On the math side you can turn the integers into a discreet N-part thing with modulus.