Positive and Negative Pulse

Okay I’ve started learning python and I’ve a few scripts that I’m taking apart piece by piece so that I can learn exactly what’s happening. Now I see a lot of 0 and 1. I’ve searched a few times and I’ve a vague idea that they mean positive and negative impulses. Can somebody please explain to me what they really are and why do we need them? Can’t we just write true and false?

Now to problem number 2. In the script there is a declaration of this at the beginning.
obj= cont.owner
That code returns the object that is connected to the controller. Well in the next few lines I see a bunch of stuff like obj[‘pathdir’] and obj[‘pathpos’]
What exactly are pathdir and pathpos? They aren’t the name of actuators or sensors, that much I’m sure of. And how can they be so suddenly used without mentioning them before?

link to the code you are talking about.