George Berkeley
He said that Locke's belief in matter was wrong. He said that even though we can see, hear, taste, touch and smell, there was no way of knowing that our senses were reacting to matter, because to find out how accurate our senses were, we would need to study the very thing we use to study. Instead, he said that our experiences are caused by God, a being that is also a mind, like us, and powerful enough to create all our ideas and senses.