After much reflection on the subject, I concluded that what causes conflict is a class of thoughts, a false grid, an illusory set of beliefs.
It holds that (1) we are separate beings whose self-interests guide our actions, (2) the planet has scarce resources, and (3) life is a competition for those resources, (4) in which only the fittest survive and the weakest go to the wall. Added to this is the conclusion that there’s nothing that can be done about the situation.
What then causes peace? Stillness of mind. Stillness is the absence of thought waves (vrittis) altogether, or, in the presence of thoughts that arise in the mind unbidden, non-attachment to them.
Such a state is being described in sayings like the flame does not flicker in a windless place and the moon can be seen reflected in the still pond.
If that cannot be attained, what’s the next most desirable development? Non-reactivity to the class of thoughts that causes conflict.