Why should we expect the multimedia principle to work? Like most ideas, psychological theory included, this expectation has its basis in philosophy. The 18th – century philosophy of Bishop George Berkeley may have been seminal in this case. Berkeley believed that nothing exists or has meaning unless it is perceived by some min. 1 Words and images are important because they give both existence and meaning matter. But Berkeley pointed out that words are abstract and generic while images are concrete and specific. The word tree will bring different meaning to different minds an also, as we might say today, different associations. An image of specific tree will suggest more specifically and strongly the meaning, the reality, that someone using the word tree has in mind.