by that of Augustine. The Jewish philosophers (as Avencebrol) laid stress upon its ontological aspect, while the Arabian philosophers (as Alfarabi and Avicenna) directed their attention more particularly to its dynamic aspect. For Bacon’s theory of Species, only the latter conception of this emanation is of significance; the emanation per virtutem as opposed to that per substantiam.[1] And the influence of Avicenna, elsewhere apparent,[2] may be seen here. The generation and propagation of Light, so essential to Avicenna’s philosophy, is fundamental for Bacon’s theory of Species.[3] Now the details of this process were not worked out by Avicenna;[4] but the fundamental notion of “effluence” is clearly enough indicated. And, what is of significance, his conception attempts to remain faithful to the Aristotelian notion of “eduction.” So too with Bacon, as we shall see, there is the clear intention to interpret and not change Aristotle’s conception. But in his description of the indestructibility of the Species, as in parts of his definition of it, there has appeared a vacillation between the notion of “eduction” and that of a very sharply defined “emission.” This latter could not well have come from Avicenna; and, besides, Bacon directly combats it, as will soon appear. How, then, account for the strong emphasis of this element in his theory of the propagation of Species? I think by reference to Alhazen.[5] For, in Alhazen the notion of emission of the Species is, one may well say, flagrantly ubiquitous. One is able to read his pages only in terms of the actual emission of the Species from the Agent and its inflow into the Patient. With this, then, are given the sources for Bacon’s no very simple notion of emanation. It is an eduction conception as attempting to follow Aristotle, probably through Avicenna, and an emission conception as taken from Alhazen.
The foregoing definition of the Species, while perfectly faithful to Bacon I believe, gives in sharper outline than is presented by him the salient and essential features of his conception. In consequence it robs his notion in part of the plausibility which his own pages show. And that is as it should be, provided the presentation is faithful. But, before passing on, let us seek to understand our Author the better, by observing the motives that worked in his mind.
In making the Species the immediate effect of the Agent, immediacy as an unanalysable ultimate is gained for the Species at least. And what is thus gained for the origin of the Species, as one effect,
- ↑ See II—434; cf. 446, for his interpretation of "per virtutem."
- ↑ E.g. I—14, 39, 43, 55, 181, 212, II—11, 13, 15, 27, 50, 54, 55, 235, 241ff., 510. Bacon was acquainted with Avicenna's "Philosophia orientalis," see II—70. A detailed study of Bacon's sources is reserved for a later work.
- ↑ It is the type of all propagation, v. II—458ff.
- ↑ Cf. Stoeckl: Gesch. d. Ph. d. Mittelalt., Mainz, 1865, II, pp. 28ff.
- ↑ Died 1038. Known chiefly for his work on Optics (ed. Risner, Basle, 1572). Bacon calls him "auctor certissimimus … nee in aliquo fefellit nos in sua scientia." (II—520.)
