intentional adhesion to a predetermined pattern throughout a whole group is totally negatived by the occurrence of occasional deviations from the pattern, such deviations are reconcilable with the belief in evolution. As pointed out in the last chapter, there is reason to think that remote ancestral traits will be obscured more or less according as the superposed modifications of structure have or have not been great or long maintained. Hence, though the occurrence of articulate animals, such as spiders and mites, having fewer than twenty segments, is fatal to the supposition that twenty segments was decided on for the three groups of superior _Articulata_, it is not incongruous with the supposition that some primitive races of articulate animals bequeathed to these three groups this common typical character--a character which has nevertheless, in many cases, become greatly obscured, and in some of the most aberrant orders of these classes quite lost."[81] Whatever may be the explanation suggested by one or another hypothesis as to the mode in which this uniformity of structure came to exist, it is certain that it does exist. Twenty segments are found in hundreds of thousands of species which are immensely different from each other in size, outline, substance and modes of existence. Here, then, is a plan. There is a pattern, on which all these different organisms are constructed with a common peculiarity. It is averred that this could not have been the result of design, because this would be to impute to the Creator a whimsical motive, namely, that he followed the pattern throughout a vast group of different organisms merely for the purpose of following it. On the contrary, it may be contended that this uniformity of plan, this repeated pattern, affords the highest probable evidence of design; and that the supposed whimsicality of motive will entirely disappear as soon as we reach a purpose which may have had very solid reasons for this uniformity of structure. When we reason about the works of the Creator, we are reasoning about the methods of a being who, we must suppose, is governed by a purpose in all that he does. In reasoning about the methods of such a being, it is entirely unphilosophical to suppose that he has done anything merely for the sake of doing it, or for the sake of exercising or displaying his powers in repetitions that had no practical value. In order to reason consistently with the supposed attributes of the Creator, we should endeavor to find the value of any given pattern which we discover in a certain very large class of organisms differing widely from each other in other respects; and in order to find that value it is by no means essential to make out that the particular plan of construction was necessary to the making of any organism whatever. The true question is, not whether twenty segments were necessary to the construction of any organism, but whether, in each of the different species, this