conditional probability is defined us:
$P(A|B) = \frac{P(A \cap B)}{P(B)}$
But if (and there is the part where i might be missing something) $P(A \cap B) = P(A) \cdot P(B)$ then:
$ \frac{P(A \cap B)}{P(B)} = \frac{P(A) \cdot P(B)}{P(B)} = P(A) $
which doesn't make any sense. Why would the formula exist in the first place. I'm confused.
Thanks for helping me :).