Brief Description: Contradiction is a method of proof in mathematics.
It can be used to prove, for example, the infinitude of primes (that there are infinite number of them), the irrationallity of square root of 2, and much more.


How it works:
Suppose we sidh to prove statement A
The logic of it works by assuming A is false. If the ¬A (negation of A) then implies a bogus result, then A must be true.

Example:
We wish to prove statement sqrt(48) < 7
(The sqrt just means 'square root of')

So we suppose the opposite of the statement.
i.e. suppose sqrt(48) >= 7 (note the equivalence must also be there)

Now we can square both sides of the inequality to get 48 >= 49 (we have contradiction!)
This is bogus, and thus, by contradiction, sqrt(48) < 7