"George Berkeley … is important in philosophy through his denial of the existence of matter—a denial which he supported by a number of ingenious arguments. He maintained that material objects only exist through being perceived. To the objection that, in that case, a tree, for instance, would cease to exist if no one was looking at it, he replied that God always perceives everything; if there were no God, what we take to be material objects would have a jerky life, suddenly leaping into being when we look at them; but as it is, owing to God’s perceptions, trees and rocks and stones have an existence as continuous as common sense supposes. This is, in his opinion, a weighty argument for the existence of God."