> without any obvious reason for it to do so without any obvious RATIONAL reason for it to do so – sometimes there is an obvious something, or a sequence of so

> without any obvious reason for it to do so without any obvious RATIONAL reason for it to do so – sometimes there is an obvious something, or a sequence of somethings, that lead up to the attack, if you trace it back. Like with a phobia where the fear not being based on rational reasoning doesn't make the reason for the fear reaction any less real.