If there any viable system in which you -can- both derive, and find useful application for, the equation 0=1 ?
James Rose Bruno Marchal wrote: > > At 13:40 26/11/04 -0500, Hal Ruhl wrote: > >What does "logically possible" mean? > > A proposition P is logically possible, relatively to > 1) a consistent set of beliefs A > 2) the choice of a deduction system D (and then consistent > means "does not derive 0=1). > > if the negation of P is not deductible (in D) from A. > > Concerning many theories, to say that a proposition > (or a set of propositions) A is logically possible > is the same as saying that A is consistent (i.e you > cannot derive 0 = 1 from it), or saying that A has a > model (a reality, a mathematical structure) satisfying > it. > > Bruno > > http://iridia.ulb.ac.be/~marchal/
