552 THE LAWS OF NATURE. 



If the kinetic theory of gases, for instance, is a matter of inference 

 rather than of observation, are we sure that we have a better guar- 

 antee for it than a previous century had for phlogiston? Our good 

 opinion of ourselves, as compared with our scientific fathers, makes 

 us think we have. Certainly I think myself that we have; and yet. 

 remember, it is the same human nature which judged that evidence 

 then, that judges this evidence now, and remember that however 

 rapidly science changes, human nature remains very much the same, 

 and always has a good conceit of itself. 



While we are venturing to utter truisms, I repeat, let us take once 

 more this one, home to ourselves, that there is a great deal of this 

 k human nature' even in the best type of the scientific man. and that 

 we of this twentieth century share it, with our predecessors, on whom 

 we look pityingly, as our successors will look on us. 



Let us repeat, and repeat once more, that though nature be external 

 to ourselves, the so-called "laws of nature"' are from within — laws of 

 our own minds — and a simple product of our human nature. Let us 

 agree that the scientific imagination can suggest questions to put to 

 nature, but not her answers. Let us read Bacon again, and agree 

 with him that we understand only what we have observed. Finally 

 let us add that we never understand even that, in the fullness of its 

 meaning, for remember that of all the so-called laws of nature, the 

 most constantly observed and the most intimately and personally 

 known to us are those of life and death — and how much do we know 

 about the meaning of them? 



