George Berkeley also known as Bishop Berkeley was an 18th century philosopher. His theory of \"immaterialism\" was later referred to as \"subjective idealism. This theory, summed up in his dictum, \"Esse est percipi,\" which states that individuals can only directly know sensation and ideas of objects not abstractions such as matter. | Three Dialogues between Hylas and Philonous in Opposition to Sceptics and Atheists by GEORGE BERKELEY, Paperback | Indigo Chapters