Note 87 — Chapter XVII · THE EPICUREAN VIEWS ON NATURE.

In thus explaining mental impressions, the Epicureans do not allow themselves to be disturbed by the fact that we can recall at pleasure the ideas of all possible things. The cause of this power was rather supposed to be the circumstance that we are always surrounded by an innumerable number of atom-pictures, none of which we perceive unless our attention is directed to them. Likewise the seeming motion of forms which we behold in dreams is explained by the hasty succession of similar atom-pictures, appearing to us as changes of one and the same picture.87 But besides receiving pictures supplied from without, spontaneous motion with regard to these pictures takes place on our part, a motion connected in the first instance with the soul’s motion when it receives the outward impression, but not to be regarded as a simple continuation thereof. This independent motion gives rise to opinion, and hence opinion is not so necessary or so universally true as feeling. It may agree with feeling, or it may not agree with it. It may be true or it may be false.88 The conditions of its being true or false have been previously investigated.89