utam ... aut etiam perfectionem non attribuimus." The future may see a change in even the method of discovery. "Artem inveniendi cum inventis adolescere posse, statuere debemus."[1]
Bacon owed to Aristotle his use of form, and his employment of the concept clearly reflects the source. Such and such a mode of motion is the form of heat, says Bacon, i.e., such and such a mode of motion is the cause of heat, i.e., heat is defined by its cause. Now Aristotle too defines by cause. "The knowledge of the what is the same as the knowledge of the why."[2] " But what is thunder?—the sound of fire extinguished in the clouds."[3]
So much for Bacon's inductive method of exclusions. The difficulties involved—difficulties already noted—were not to be overcome. Consequently, we find Bacon latterly laying great stress on the inductive value of Natural History. "For a small and well-ordered Natural History is the Key of all knowledge and operation."[4] Bacon's Sylva Sylvarum is an example of this recourse to Natural History. Inspired probably by the same spirit as Aristotle when he wrote his Historia Animalium, Bacon does not here show the same power of classification as the Greek philosopher. The Sylva Sylvarum is certainly not "well-ordered." On the other hand Bacon himself recognises this defect. "I have heard his lordship say, that if he should have served the glory of his own name, he had better not to have published this Natural History; for it may seem an indigested heap of particulars, and cannot have that lustre which books cast into methods have; but that he resolves to prefer the good of men, and that which might best secure it, before anything that might have relation to himself."[5]
Bacon's reliance, latterly, on Natural History peculiarly emphasises the importance he always attached to observation of the facts of experience. By such observation he frequently distin-
