INDUCTIONS IMPROPERLY SO CALLED. 327 



if the wheels were no longer supposed to be material, but 

 were reduced to mere geometrical spheres or circles, they 

 were not the less products of the mind alone, something 

 additional to the facts observed. The same is the case in 

 all other discoveries. The facts are known, but they are 

 insulated and unconnected, till the discoverer supplies from 

 his own store a principle of connexion. The pearls are 

 there, but they will not hang together till some one provides 

 the string." 



Let me first remark that Dr. Whewell, in this passage, 

 blends together, indiscriminately, examples of both the pro- 

 cesses which I am endeavouring to distinguish from one 

 another. When the Greeks abandoned the supposition that 

 the planetary motions were produced by the revolution of 

 material wheels, and fell back upon the idea of " mere geo- 

 metrical spheres or circles," there was more in this change of 

 opinion than the mere substitution of an ideal curve for a 

 physical one. There was the abandonment of a theory, and 

 the replacement of it by a mere description. No one would 

 think of calling the doctrine of material wheels a mere de- 

 scription. That doctrine was an attempt to point out the 

 force by which the planets were acted upon, and compelled to 

 move in their orbits. But when, by a great step in philosophy, 

 the materiality of the wheels was discarded, and the geome- 

 trical forms alone retained, the attempt to account for the 

 motions was given up, and what was left of the theory was a 

 mere description of the orbits. The assertion that the planets 

 were carried round by wheels revolving in the inside of other 

 wheels, gave place to the proposition, that they moved in the 

 same lines which would be traced by bodies so carried : which 

 was a mere mode of representing the sum of the observed 

 facts; as Kepler's was another and a better mode of repre- 

 senting the same observations. 



It is true that for these simply descriptive operations, as well 

 as for the erroneous inductive one, a conception of the mind was 

 required. The conception of an ellipse must have presented 

 itself to Kepler's mind, before he could identify the planetary 

 orbits with it. According to Dr. Whewell, the conception 



