Objects do not exist outside sense perception.Bundle Theory again: objects are perceived as a collection, or bundle, of characteristics: apple=colour, shape, smell, taste. If we remove these characteristics, we cannot conceive of an apple through pure reason.Hume’s theory of knowledge suggests that there are some things humans can never know because it denies the idea of cause and effect. As a result, his theory suggests that humans can never make links between events or know for sure that something will happen as a result of something else. This means that all knowledge derived from scientific investigations may be false.