262 Transactions of the American Institute. 



is a creation of the mind. The senses do not declare it in any way 

 whatsoever. We do not see the solar system ; we see simply planets^, 

 without discerning at all their relation to the sun. Indeed, the con- 

 ceptions of the mind come in directly to contradict appearances. 

 The senses have nothing to do with this action of the mind. We do- 

 not see the solar system — we conceive it. Or, take, again, the theo- 

 ries of chemistry in connection with molecules. A molecule may be 

 more complex than the solar system — more complex in the number 

 of bodies which make it up, in the relation M'hich these sustain to 

 each other, and in their varying hold upon one another. This whole 

 conception, again, is a conception which came forth from the mind, 

 the eye never so much as reaching the molecule, never so much as 

 discerning that to which this whole theory pertains — far less discern- 

 ing the atoms which make up molecules — still less discerning the 

 relation of these atoms one to another. This whole idea, by which 

 this system of molecules becomes as complicated as the solar system,, 

 is a creation of the mind. [Applause.] 



Ideas. 



These are conceptions, due wholly to the mind, are furnished by it 

 in obedience to certain suggestions, under certain ideas brought for- 

 ward by itself. It is the ideas of space and time which lead the 

 thoughts to the construction of tlie solar system. If the successive 

 appearances of the heavens — the sensible data which the astronomer 

 uses — were regarded by him as mere photographs, presenting certain 

 points of light on a plane surface, there would be nothing in them to 

 call forth a theory of their relations. It is because of the vast spaces 

 in which they are thought to move, and the times occupied in this 

 change of place, that the mind is started in the pursuit of a consist- 

 ent theory. Atoms and molecules are accepted, and this connection 

 with each other figured, because the idea of cause and efiect is thus 

 met and satisfied. Without this antecedent idea, we should lieive no 

 impulse to the formation of a theory. Why does the Cardiff Giant 

 so vex our thoughts? Why can we not pass it by as so much stone, 

 with the same indifference that the dog regards it 'i I>ecause of this 

 notion of cause and effect, pressing us to form some theory of its ori- 

 gin. Thus, universally, it is some additional notion which the mind 

 brings to external facts, that makes them fruitful — productive of sci- 

 entific conceptions. 



This use of ideas is a familiar fact of our daily experience. A man 



