PRIMARY CONCEPTS OF MODERN SCIENCE. 221 



state here) to combine with hydrogen in the ratio of one volume to 

 four, so as to yield two volumes of marsh-gas. 



It seems to be evident, then, that the typical and primary state of 

 matter is, not the solid, but the gas. And, this being so, it follows 

 that the molecular evolution of matter conforms to the law of all evo- 

 lution in proceeding from the indeterminate to the determinate, from 

 the simple to the complex, from the gaseous to the solid form. This 

 is no longer a mere presumption ; if the nebular hypothesis, so called, 

 after being stripped of its non-essential features, is recognized as a 

 true theory — as it is by all the prominent physicists of the day since 

 the recent revelations of the spectroscope — the gaseous form of matter, 

 in fact, precedes the liquid and solid forms in the order of Nature, 

 and the solid is not the initial, but the concluding term of material 

 evolution. Inasmuch, therefore, as the explanation of any phenomenon 

 consists in the exhibition of its genesis from its simplest beginnings, 

 or from its earliest forms, the gaseous form of matter is the true basis 

 for the explanation of the solid form, and not conversely the solid for 

 the explanation of the gas. 



From the foregoing considerations I take it to be evident that the 

 true relation between the molecular states of matter is the exact re- 

 verse of that universally assumed. The universality of this assump- 

 tion, however, indicates that it is not due to a mere chance error of 

 speculation, but to some natural bias of the mind. The question 

 arises, therefore : "What is the origin of this prevalent delusion re- 

 specting the constitution of matter? I believe the answer to this 

 question to be exceedingly simple, and important in proportion to its 

 simplicity. There are certain fallacies to which the human intellect 

 is liable by reason of the laws of its growth which I propose to call 

 structural fallacies, one of which is that the intellect tends to con- 

 found the order of the genesis of its ideas respecting material objects 

 with the order of the genesis of these objects themselves. It is well 

 known that the progress of our knowledge depends upon analogy — 

 upon a reduction of the Strange and Unknown to the terms of the Fa- 

 miliar and Known. In a certain sense it is true, what has been often 

 said, that all cognition is recognition. " Man constantly institutes 

 comparisons," says Pott (" Etymologische Forschungen," ii., 139), 

 " between the new which presents itself to him, and the old which he 

 already knows." That this is so is shown by the development of lan- 

 guage. The great agent in the evolution of language is metaphor — 

 the transference of a word from its ordinary and received meaning to 

 an analogous one. This transference of the name descriptive of a 

 known and familiar thing to the designation of an unknown and un- 

 familiar thing typifies the proceeding of the intellect in all cases where 

 it deals with new and strange phenomena. It assimilates these phe- 

 nomena to those which are known ; it identifies the Strange, as far as 

 possible, with the Familiar ; it apprehends that which is extraordinary 



