I understand where you're coming from tirnanog and - while I have no wish to slate someone else's religious beliefs - I don't believe in God or souls, so for me it carries no weight.
Also, dogs are capable of learning consequences for their actions, or 'reasoning', and choosing not to repeat those actions if the consequences are unpleasant. A lot of it is Pavlovian, but they will try and push it every now and then to test boundaries - like a toddler.
I do think that some dogs are just more prone to aggression than others - just like humans.
And some dogs are mad.