- David Hume (1711-1776) : David Hume agreed with Berkeley that humans could experience only their own subjective reality but disagreed with Berkeley's contention that humans could assume that their perceptions accurately reflect the physical world because God would not deceive us. For Hume, we can be sure of nothing. Even the notion of cause and effect, which is so important to Newtonian physics, is nothing more than a habit of thought. Hume distinguished between impressions, which are vivid, and ideas, which are faint copies of impressions.