As humans (and as mammals) we're "on the long leash of evolution" because we can think through our actions and mentally prepare for calamity. We do this even du

As humans (and as mammals) we're "on the long leash of evolution" because we can think through our actions and mentally prepare for calamity. We do this even during sleep. (The organisms that can't are "on the short leash" because behaviour modifications happen through death of the maladjusted.) This ability is selected for in nature because it keeps us out of harms way. Unfortunately for some people it can overshoot into crippling worry. Sometimes when walking over a bridge the thought comes to me: "What if it started collapsing?" And I'll consider my options only to conclude: I'd be smashed to bits not matter what I did. It takes some force of will not to walk faster at that point. I have a friend who sometimes can't cross bridges for the fear of leaping off. Both thoughts are irrational in the sense that the chance of it occurring are remote. Still, the same kind of thoughts have saved my life on numerous occasions. In traffic for example. I like the picture of these thoughts being the (sometimes dramatic) background music of our lifes.