Respecting the more philosophic questions it is necessary to observe, that the Evolution-theory will not form a topic of the present chapter. It is excluded for two reasons. One, that we are now trying to put a value on the argument from Design _per se_, and not to compare it with rival theories. The other reason springs from the subject of Evolution itself--it is too extensive to be thus briefly treated--and the sum of this Essay must be taken together as furnishing a counter statement to the manner in which it has been employed by certain of its ardent advocates.[14] We hope for a further advantage from the method proposed. The cause of truth ought to gain from being looked at on more than one side; and, whatever be the worth and true effect of reasoning from Design, we may expect by this method to display it adequately. The word itself, like all figurative terms--or words used in a secondary sense--is by no means free from ambiguity. It has, in common parlance, several shades of signification. Design being the centre of Paley's argument, and containing the one idea which gives force to all the rest: his first object was to fix the sense in which he employed it. He did so by using an illustration. To explain by comparison is always a popular resource, some serious drawbacks notwithstanding. Almost every one prefers that an author should use a sparkling similitude which tells a great deal, rather than write what looks like a grammar and dictionary of his science. Analysis and induction require thought on the part of him who employs them--thought also on the part of a reader determined to understand what he reads. Paley saw all this thoroughly, and at the beginning of his book employed the now celebrated comparison taken from a watchmaker and a watch. His judgment received support from the popularity he enjoyed, and from the way in which everybody borrowed his illustration.[15]