can they vary?  If individuals alone exist, how can the differences which may be observed among them prove the variability of the species?  To which we reply by asking, Which does the question refer to, the category of thought, or the individual embodiment?  If the former, then we would remark that our categories of thought vary from time to time in the readiest manner.  And, although the Divine thoughts are eternal, yet they are manifested in time and succession, and by their manifestation only can we know them, how imperfectly!  Allowing that what has no material existence can have had no material connection and no material variation, we should yet infer that what had intellectual existence and connection might have intellectual variation; and, turning to the individuals which represent the species, we do not see how all this shows that they may not vary.  Observation shows us that they do.  Wherefore, taught by fact that successive individuals do vary, we safely infer that the idea or intention must have varied, and that this variation of the individual representatives proves the variability of the species, whether subjectively or objectively regarded.

Each species or sort of chair, as we have said, has its varieties, and one species shades off by gradations into another.  And—­note it well—­these numerous and successively slight variations and gradations, far from suggesting an accidental origin to chairs and to their forms, are very proofs of design.

Again, edifice is a generic category of thought.  Egyptian, Grecian, Byzantine, and Gothic buildings are well-marked species, of which each individual building of the sort is a material embodiment.  Now the question is, whether these categories of thought may not have been evolved, one from another, in succession, or from some primal, less specialized, edificial category.  What better evidence for such hypothesis could we have than the variations and grades which connect one of these species with another?  We might extend the parallel, and get some good illustrations of natural selection from the history of architecture, the probable origin of the different styles, and their adaptation to different climates and conditions.  Two qualifying considerations are noticeable.  One, that houses do not propagate, so as to produce continuing lines of each sort and variety; but this is of small moment on Agassiz’s view, he holding that genealogical connection is not of the essence of species at all.  The other, that the formation and development of the ideas upon which human works proceed is gradual; or, as the same great naturalist well states it, “while human thought is consecutive, Divine thought is simultaneous.”  But we have no right to affirm this of Divine action.

We must close here.  We meant to review some of the more general scientific objections which we thought not altogether tenable.  But, after all, we are not so anxious just now to know whether the new theory is well founded on facts as whether it would be harmless, if it were.  Besides, we feel quite unable to answer some of these objections, and it is pleasanter to take up those which one thinks he can.