can be, and nearly always is, controlled by the mind.

Last of all there is the repulsion and loathing for the whole business
of war, with its bloody ruthlessness, its fiendish ingenuity, and
its insensate cruelty, that comes to a man after a battle, when the
tortured and dismembered dead lie strewn about the trench, and the
wounded groan from No-Man's-Land. But neither is that the fear of
death. It is a repulsion which breeds hot anger more often than cold
fear, reckless hatred of life more often than abject clinging to it.

The cases where any sort of fear, even for a moment, obtains the
mastery of a man are very rare. Sometimes in the case of a boy,
whose nerves are more sensitive than a man's, and whose habit of
self-control is less formed, a sudden shock will upset his mental
balance. Sometimes a very egotistical man will succumb to danger long
drawn out. The same applies to men who are very introspective. I have
seen a man of obviously low intelligence break down on the eve of an
attack. The anticipation of danger makes many men "windy," especially
officers who are responsible for other lives than their own. But even
where men are afraid it is generally not death that they fear. Their
fear is a physical and instinctive shrinking from hurt, shock, and the
unknown, which instinct obtains the mastery only through surprise, or
through the exhaustion of the mind and will, or through a man being
excessively self-centred. It is not the fear of death rationally
considered; but an irrational physical instinct which all men possess,
but which almost all can control.