Prof. W. A. Norton on Molecular Physics. 35 



pounded, occupy precisely the same hypothetical position that 

 all former physical theories have at first done — as that of uni- 

 versal gravitation, the undulatory theory of light, &c. It is by 

 triumphantly withstanding all possible tests that these and other 

 theories have come to be admitted among the established truths 

 of physical science. It is in this way alone that physical science 

 has hitherto made all its great advances. In no instance has a 

 physical theory sprung into existence, Minerva-like, in full 

 armed panoply, the complete full-grown impersonation of wis- 

 dom and truth. 



It does not follow, then, as our author intimates, because 

 such theories have had, and as I conceive must continue in 

 each new instance to have, more or less of a hypothetical foun- 

 dation, that no physical theory can lead to established truths. 

 The deductions from it have, it is true, no higher certainty, as 

 mere deductions, than the fundamental induction from which 

 they are derived; but every legitimate deduction that accords 

 w r ith known facts, furnishes thereby a new confirmation of the 

 essential truth of the theory. It gains assurance of strength by 

 its victories, and, when crowned with years of triumph, is worthy 

 of all honour, despite its humble origin. 



Professor Bayma conceives that the time has arrived when a 

 theory of molecular physics can be securely erected upon a few 

 philosophical principles which may be regarded as established 

 truths, and that the legitimate deductions from the theory will 

 have the same character of certainty. If this claim could be 

 admitted, I should be far from desiring to put a single straw in 

 the way of his success, and would gladly recognize the " eternal 

 verities " evolved from his philosophy. Nor would there be of 

 necessity any conflict between us; for in proportion to the 

 strength of my confidence iu the essential truth of my own 

 theory of the modes of evolution of phenomena, would be the 

 strength of my conviction that his theory must embrace my own 

 generalizations within its comprehensive grasp, though placing 

 them in a new attitude and on a deeper foundation. But I can- 

 not but entertain a decided conviction that our author's claim, 

 that his legitimate theoretical deductions are positive certain- 

 ties, rests on fallacious grounds. It implies that his fundamental 

 principles, whether formally expressed or implied, are all either 

 universally admitted truths, or truths which he has himself de- 

 monstrated. Now certain of these principles do not, in the na- 

 ture of things, admit of positive proof. They cannot have any 

 other foundation than certain conceptions with regard to matter 

 or active powers which can only be regarded as mere assump- 

 tions. For example, it is laid down as a fundamental principle 

 that matter in its ultimate analysis is made up of absolute 



D2 



