G2 METHOD OF DISCOVERY. 



is, that tea-pots and spoons do not go out of a window 

 spontaneously, and you are satisfied that, as they are 

 not now where you left them, they have been removed. 

 In the third place, you look at the marks on the win- 

 dow-sill, and the shoe-marks outside, and you say that 

 in all previous experience the former kind of mark 

 has never been produced by anything else but the 

 hand of a human being ; and the same experience shows 

 that no other animal but man at present wears shoes 

 with hob-nails on them such as w^ould produce the 

 marks in the gravel. I do not know, even if we could 

 discover any of those " missing links " that are talked 

 about, that they would help us to any other conclusion ! 

 At any rate the law which states our present experience 

 is strong enough for my present purpose. You next 

 reach the conclusion, that as these kinds of marks have 

 not been left by any other animals than men, or are 

 liable to be formed in any other way than by a man's 

 hand and shoe, the marks in question have been formed 

 by a man in that way. You have, further, a general 

 law, founded on observation and experience, and that, 

 too, is, I am sorry to say, a very universal and unim- 

 peachable one, — that some men are thieves ; and you 

 assume at once from all these premisses — and that is 

 what constitutes your hypothesis — that the man who 

 made the marks outside and on the window-sill, opened 

 the window, got into the room, and stole your tea-pot 

 and spoons. You have now arrived at a Vera Causa ; 

 — you have assumed a Cause which it is plain is com- 

 petent to produce all the phenomena you have observed. 

 You can explain all these phenomena only by the hy- 

 pothesis of a thief. But that is a hypothetical conclu- 

 sion, of the justice of which you have no absolute proof 



