Prophets look at the world as finite, and people as constrained by their environment. Wizards see possibilities as inexhaustible, and humans as wily managers of the planet. One views growth and development as the lot and blessing of our species; others regard stability and preservation as our future and our goal. Wizards regard Earth as a toolbox, its contents freely available for use; Prophets think of the natural world as embodying an overarching order that should not casually be disturbed.
Human populations will reproduce beyond their means of subsistence unless they are held back by practices like celibacy, late marriage, or birth control. But the reproductive urge is so strong that people at some point will stop restricting births and have children willy-nilly. When this happens, populations inevitably grow too large to feed. Then disease, famine, or war step in and brutally reduce human numbers until they are again in balance with their means of subsistence — at which stage they will increase again, beginning the unhappy cycle anew.