We cannot represent the three dimensions of space save by setting three lines at right angles to one another from the same point(kB155)
We cannot represent the three dimensions of space save by setting three lines at right angles to one another from the same point(kB155)
I confine myself as a rule to three dimensions, since a further extension has little theoretic interest. Three dimensions are far more interesting than two because, as we have seen, the greater part of projective geometry i.e. everything dependent upon the quadrilateral construction- is impossible with less than three dimensions, unless the uniqueness of the quadrilateral construction be taken as an axiom(pm399)