>>12864373I'm assuming you're talking about the 5th axiom.
Take two lines which may are may not be parallel and consider a third line that intersects both of them. This third line forms interior angles, 2 on each side of the line. Add up the angles on one side, if they sum up to be less than 180 degrees then the two initial lines will eventually interest some distance away on the same side as the two interior angles.
Looking at my pic, the two angles, alpha and beta, sum to be less than 180 degrees so the angles eventually intersect on the same side. If you picked the angles on the other side you would conclude the lines would not interest in that direction since the angles add up to be more than 180 degrees.
>>12864399He was, by Hilbert.
