0 for an even stronger reason than one that has already been accepted: --
The proposition is incomprehensible to us, and hence a fortiori we cannot be justified in believing it.
1 used to describe an argument that gives a stronger reason than one that has already been accepted: --
his a fortiori argument
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Можем да го завършим стъпка по стъпка, колкото и дълъг да е пътят и не може да бъде завършен, колкото и кратък да е пътят, ако дори не маркирате отпечатъка си.