I understand Implication, as follows:
p = rain stopped.
q = i go out.
p->q = if "rain stopped" then "i go out".
p q p->q
-----------------------------------------------------------------------------------------
F F T
(rain is not stopped) (i don't go out) (if rain is not stopped, I don't go out)
F T F
(rain is not stopped) (i go out) (if rain is not stopped, I go out)
T F F
(rain is stopped) (i don't go out) (if rain is stopped, I don't go out)
T T T
(rain is stopped) (i go out) (if rain is stopped, I go out)
But, this video says that $F \rightarrow T = T$
Best Answer
The fact that the conditional $$P\to Q$$ is true whenever its antecedent $P$ is false (principle of explosion; vacuous truth) is actually so by definition:
$P\to Q\,$ is a truth function that is tautologically equivalent to $\,\lnot P\lor Q.$
So, $P\to Q\,$ is false precisely when $P$ is true but $Q$ false.
To be clear: whenever $P$ is false, the assertion $P\implies Q\,$ gives no information about whether $Q$ is true.
Summarising these two explanations of the motivation for the above definition:
if we insist, to the contrary, that False$\to$True be false, then, unfortunately, these violations of natural deduction arise: $$\text{$A$ is true and $B$ is false $\implies\Big[(A\land B)\to A\Big]\;$is false!}$$ and $$\Big[\forall n\in\mathbb Z \;\big(n \text{ is a multiple of }4\, \to \,n \text{ is even}\big)\Big]\;\text{is false}!$$
It is worth noting that in logic/mathematics, $P$ need not cause $Q$ for $P$ to imply $Q,$ that is, for the material conditional $\,P\to Q\,$ to actually be true.
After all, the logical connective $\,\to,$ being a truth-functional operator, cares about truth states without considering the flow of time.