Why be afraid of savage dogs if you can’t be sure they want to hurt you? Just because they’re barking and baring their teeth and running towards you doesn’t mean they’ll definitely bite. And even if they do, it won’t necessarily hurt. Why care about oncoming traffic when you cross the road? Those carts might not hit you. Who really knows? And what difference does it make if you are alive or dead anyway? Somehow Pyrrho managed to live out this philosophy of total indifference and conquer all the usual and natural human emotions and patterns of behaviour.
I find the last sentence is too complex to understand.
Which noun does usual and natural modify? "human emotions" or "patterns of behaviour" or both of them?