THE EXPERIMENTAL STUDY OF NATURE. 373 



ancient an authority than Aristotle, that there is no such thing as in- 

 nate knowledge — that knowledge of every kind has to he acquired, 

 and that it is based upon perceptions reaching the mind through the 

 senses. Harvey thus epitomizes what was said by Aristotle respect- 

 ing the manner in which the knowledge appertaining to science is ac- 

 quired : " The thing perceived by sense remains ; from the perma- 

 nence of the thing perceived results memory ; from multiplied memory, 

 experience ; and from experience, universal reason, definitions, and 

 maxims or common axioms." In its elementary form, knowledge con- 

 sists of simple inferences drawn in a direct manner from impressions. 

 A child once burned afterward shuns the fire. From the impression 

 received an inference is framed which forms the foundation for future 

 action. The same kind of operation determines the conduct of the 

 lower animals. By mental action these simple inferences may be 

 raised into or give rise to knowledge of a higher kind. This is what 

 for science is required to be done. The exercise of the intellectual 

 faculties must be brought into operation, in order that what we acquire 

 through perception may be shaped into the knowledge that it is desired 

 to obtain. The object in science is to discover the facts and laws of 

 Nature ; and, to apply the intellect advantageously for the purpose, 

 there must be some systematic course, some method or art of reason- 

 ing, adopted. The system employed up to Harvey's time was the 

 Aristotelian, or syllogistic — a system which, while being well adapted 

 for affording proof upon any particular point, is ill adapted for pro- 

 moting the advance of knowledge. When through the major and 

 minor premises of a syllogism I draw a conclusion, a point is proved, 

 but no real addition is made to our stock of knowledge. For instance 

 when in accordance with the rules of the syllogistic art I say — "All 

 men are mortal : Thomas is a man, therefore Thomas is mortal " — I 

 start with the general proposition in the major premise that " all men 

 are mortal," and arrive at the conclusion, through the minor premise, 

 that a particular individual is mortal. A certain attribute — mortality 

 — is asserted to be possessed by a class. A member of the class must 

 also possess the attribute, and this is all the information that my 

 syllogistic conclusion has given me — that the individual named 

 Thomas possesses the attribute of mortality, which belongs as a gen- 

 eral character to the group of individuals of which he is a member. 

 The two premises of the syllogism already consist of established 

 truths, and for a syllogism to be valid there must be nothing con- 

 tained in the conclusion beyond what is asserted in the premises. The 

 train of reasoning, therefore, is not adapted to lead us to the ac- 

 quirement of new knowledge. The essence, indeed, of the system 

 consists in proceeding from generals to particulars. The major prem- 

 ise with which we start is, in reality, a general proposition, contain- 

 ing knowledge which has been acquired — not, it is true, by the me- 

 thodical application of induction, but nevertheless after the manner of 



