ABSTRACTION. 461 



cases of the absence of the phenomenon, cases of motion not spontaneous. 

 The conception was hence " inappropriate." We may add that, in the case 

 in question, no conception would be appropriate ; there is no agreement 

 which runs through all the cases of spontaneous or apparently spontaneous 

 motion and no others ; they can not be brought under one law ; it is a case 

 of Plurality of Causes.* 



§ 5. So much for the first of Dr. Whewell's conditions, that conceptions 

 must be appropriate. The second is, that they shall be " clear :" and let us 

 consider what this implies. Unless the conception corresponds to a real 

 agreement, it has a worse defect than that of not being clear : it is not ap- 

 plicable to the case at all. Among the phenomena, therefoi-e, which we are 

 attempting to connect by means of the conception, we must suppose that 

 there really is an agreement, and that the conception is a conception of 

 that agreement. In order, then, that it may be clear, the only requisite is, 

 that we shall know exactly in what the agreement consists ; that it shall 

 have been carefully observed, and accurately remembered. We are said 

 not to have a clear conception of the resemblance among a set of objects, 

 when we have only a general feeling that they resemble, without having 

 analyzed their resemblance, or perceived in what points it consists, and 

 fixed in our memory an exact recollection of those points. This want of 

 clearness, or, as it may be otherwise called, this vagueness in the general 

 conception, may be owing either to our having no accurate knowledge of 

 the objects themselves, or merely to our not having carefully compared 

 them. Thus a person may have no clear idea of a ship because he has 

 never seen one, or because he remembers but little, and that faintly, of 

 what he has seen. Or he may have a perfect knowledge and remembrance 

 of many ships of various kinds, frigates among the rest, but he may have 

 no clear but only a confused idea of a frigate, because he has never been 

 told, and has not compared them sufficiently to have remarked and remem- 

 bered, in what particular points a frigate differs from some other kind of 

 ship. 



It is not, however, necessary, in order to have clear ideas, that we should 

 know all the common properties of the things which we class together. 

 That would be to have our conception of the class complete as well as 

 clear. It is sufficient if we never class things together without knowing 

 exactly why we do so — without having ascertained exactly what agree- 

 ments we are about to include in our conception ; and if, after having thus 

 fixed our conception, we never vary from it, never include in the class any 



* Other examples of inappropriate conceptions are given by Dr. Wliewell {Phil. Ind. Sc. 

 ii., 185) as follows: "Aristotle and his followers endeavored in vain to account for the me- 

 chanical relation of forces in the lever, by applying the inappropriate geometrical concep- 

 tions of the properties of the circle :' they failed in explaining the form of the luminous spot 

 made by the sun shining through a hole, because they applied the inappropriate conception 

 of a circular quality in the sun's light : they speculated to no purpose about the elementary 

 composition of bodies, because they assumed the inappropriate conception of likeness between 

 the elements and the compound, instead of the genuine notion of elements merely determining 

 the qualities of the compound." But in these cases there is more than an inappropriate con- 

 ception ; there is a false conception ; one which has no prototype in nature, nothing corre- 

 sponding to it in facts. This is evident in the last two examples, and is equally true in the 

 first ; the "properties of the circle" which were referred to, being purely fantastical. There 

 is, therefore, an error beyond the wrong choice of a principle of generalization ; there is a 

 false assumption of matters of fact. The attempt is made to I'esolve certain laws of natuie 

 into a more general law, that law not being one which, though real, is inappropriate, but one 

 wholly imaginary. 



