As we study the Third Foundation of the Satipatthana Sutta we ask what is the mind and how does it seem to create a sense of self having the experience of an external world?
Desire forms the sense of self by fracturing the mind into what it wants compared to what it has. In moving with what it wants, it has to dismiss or resist reality (what it has) and form its own imaginative response. The sense of self is part of that fantasy buildup and has a central role in keeping it going.
Aversion and desire work together to entrap the mind within its own projections and divide the whole into parts. The opposite of what I desire is feared and visa versa. Because the mind is a single whole, when we pit what we like against what we do not, repetitive aversive and desiring images noisily dance through the mind in opposition to the contentment of the abiding wholeness.
Fear divides the mind by convincing us that the present is in the crosshairs of an approaching disaster. We therefore need to harness the power of our thinking and take flight physically and mentally away from now. If presence is maintained, fear has no way to access the moment except by projecting into the future.