CHAP.
XVI.

(4) Standard of truth subjective.

round at a distance will appear round close at hand. In that case if the real perception corresponds to our supposition, our opinion is true, otherwise it is false. At other times we suppose that certain appearances are due to secret causes; for instance, that empty space is the cause of motion. If all appearances tally with their explanations we may consider our suppositions correct; if not our suppositions are incorrect. 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. 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.

Little pains seem to have been taken by Epicurus to overcome the difficulties by which his 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

Epicur. in Diog. 50; Ibid. 33; Sext. vii. 212. The object of a future sensation is called by Diog. 38, Tò πроoμévov. Diog. x. 34, himself gives a perverted explanation of this term, which probably misled Steinhart.

2 Sext. 1. c. 213.

The two tests of truth, proof and absence of refutation, do not,

therefore, refer to the same cases. Our suppositions in respect of external appearances must be proved, in order to be true; our impressions of the secret causes of these appearances must not be refuted. The former test applies to opinions regarding τὸ προστ μévov; the latter, to opinions regarding Tò &dпλov. Diog. 38.

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 as to their causes.

This line of argument, however, only removes the difficulty one step further. Sensation is said always to reproduce faithfully the picture which affects the organs of sense, but the pictures do not always reproduce the object with equal faithfulness. How then can a faithful picture be known from one which is not faithful? To this question the Epicurean system can furnish no real answer. Το say that the wise man knows how to distinguish a faithful from an unfaithful picture 2 is to despair of an absolute.

1 Compare the passages in Sext. vii. 206.

2 Cic. Acad. ii. 14, 45: Nam qui voluit subveniro erroribus

Epicurus iis, qui videntur con-
turbare veri cognitionem, dixit-
que sapientis esse opinionem a
perspicuitate sejungere, nihil pro-

CHAP.

XVI.

CHAP.
XVI.

standard at all, and to make the decision of truth or
error depend upon the individual's judgment. Such
a statement reduces all our impressions of the pro-
perties of things to a relative level. If sensation
does not show us things themselves but only those
impressions of them which happen to affect us, it
does not supply us with a knowledge of things as they
are, but as they happen to be related to us.
It was,
therefore, a legitimate inference from this theory of
knowledge for Epicurus to deny that colour belongs
to bodies in themselves, since some only see colour in
the dark, whilst others do not. Like his predecessor,
Democritus, he must have been brought to this view
by his theory of atoms. Few of the properties belong
to atoms which we perceive in things, and hence
all other properties must be explained as not belong-
ing to the essence, but only belonging to the appear-
ance of things. The taste for speculation was,
however, too weak, and the need of a direct truth of
the senses too strong in Epicurus for him to be able
to turn his thoughts in this direction for long.
Whilst allowing to certain properties of things only
a relative value, he had no wish to doubt the reality

fecit, ipsius enim opinionis er-
rorem nullo modo sustulit.

1 Plut. Adv. Col. 7, 2 (Stob.
Ecl. i. 366; Lucr. ii. 795): &
Ἐπίκουρος οὐκ εἶναι λέγων τὰ
χρώματα συμφυῆ τοῖς σώμασιν,
ἀλλὰ γεννᾶσθαι κατὰ ποιάς τινας
τάξεις καὶ θέσεις πρὸς τὴν ὄψιν.
For, says Epicurus, οὐκ οἶδα ὅπως
δεῖ τὰ ἐν σκότει ταῦτα ὄντα φῆσαι
χρώματα ἔχειν. Often some see
colour where others do not; où

μᾶλλον οὖν ἔχειν ἢ μὴ ἔχειν χρῶμα ῥηθήσεται τῶν σωμάτων ἕκαστον.

2 Simpl. Categ. 109, 8 (Schol. in Arist. 92, a, 10): Since Democritus and Epicurus deprive atoms of all qualities except those of form and mode of combination, ἐπιγίνεσθαι λέγουσι τὰς ἄλλας ποιότητας, τάς τε ἁπλᾶς, οἷον θερμότητας καὶ λειότητας, καὶ τὰς κατὰ χρώματα καὶ τοὺς xvμoús. Lucret. 1. c.

of objects nor to disparage the object-pictures which furnish us with sensations.1

CHAP.
XVI.

CHAPTER XVII.

CHAP.
XVII.

views on

nature.

(1) Object, value, and

method of the study of nature.

THE EPICUREAN VIEWS ON NATURE.

IF EPICURUS and his followers underrated logic, to natural science they attached a very considerable A. General value. This value was, however, given to science simply from a sense of the practical advantages which a knowledge of nature was seen to confer in opposing superstition. Otherwise the study of nature was a thing they would have readily dispensed with.' Such being their attitude of mind, the Epicureans were, as might have been expected, indifferent about giving a complete and accurate explanation of phenomena. Their one aim was to put forward such a view of nature as would do away with the necessity of supernatural intervention, without at the same time pretending to offer a sufficient solution of the problems raised by science.2 Whilst, therefore, devoting considerable attention to natural science,3 Epicurus does not seem to have considered certainty to