4.2 Irrational Method
When demonstrating the same thing, there is also this method of doing it. When p implies q needs to be demonstrated, we still assume the condition with assume p in the proof. Then we will deny the conclusion by stating assume not q.
p implies q
proof
assume p;
assume not q;
......
......
thus contradiction;
end;
And then we will lead from this and state thus contradiction. It means that a irrational method was used. If we assume that it is neither p nor q, it means that an inconsistency occurred.