[1142] In the first case the test of the truth of an opinion is that it is supported by experience; in the latter that it is not refuted by experience. [1143] Have we not here all the leading features of a theory of knowledge based purely on sensation? The Epicurean’s interest in these questions was, however, far too slight to construct with them a developed theory of materialism. [(4) Standard of truth subjective.] Little pains seem to have been taken by Epicurus to overcome the difficulties by which this view was beset. If all sensations as such are true, the saying of Protagoras necessarily follows that for each individual that is true which seems to him to be true, that contrary impressions about one and the same object are true, and that deceptions of the senses, so many instances of which are supplied by experience, are really impossible. To avoid these conclusions, Epicurus maintained that for each different impression there is a different object-picture. What immediately affects our senses is not the object itself, but a picture of the object, and these pictures may be innumerable, a different one being the cause of each separate sensation. Moreover, although the pictures emanating from the same object are in general nearly alike, it is possible that they may differ from one another owing to a variety of causes. If, therefore, the same object appears different to different individuals, the cause of these different sensations is not one and the same, but a different one, and different pictures must have affected their senses. If our own sensations deceive us, the blame does not belong to our senses, as though they had depicted to us unreal objects, but to our judgment for drawing unwarranted inferences from pictures [1144] as to their causes.