The watch represents the world; its complex and intricate workings representing those of nature, for example the way that all animals are so well adapted to their surroundings. Just as the apparent design of the watch implies a designer, so to does the apparent design of the world. This designer, Paley claims, is God.
Paley makes a number of additional statements to his analogy, in order to uphold its relevance in anticipation of criticism. Firstly, he claims that it would not matter if we had never seen a watch before (as we have never seen another world before); nor would it have any bearing on the relevance of the analogy if we didn’t recognise its functions (as we don’t recognise all of the worlds functions), or even if it didn’t function properly at all (as the world doesn’t always function properly). In each of the above Paley claims that we would still recognise some intelligent design, and thus still imply some intelligent designer.
Q: What are the main criticisms of the teleological argument?
There have been many different criticisms of the teleological argument, the most fundamental and damaging of which coming, in my opinion, from David Hume in his Dialogues Concerning Natural Religion.
Hume points out that any world or universe is bound to appear designed for the simple reason that if it had no order which may constitute or replicate a design, it would never have sustained or continue to sustain itself in existence. In other words, without this order (or apparent design), there could be no universe. More broadly speaking, nothing is able to sustain its existence unless it is adapted to a considerable degree (constituting design). For example, if humans were not adapted to their surroundings, such as if we couldn't breath air, we would not be able to exist; or even have been able to come into existence in the first place.
Another criticism of Hume's, more specifically suited to Paley's argument, is that drawing an analogy between the universe and a human object is completely illegitimate, for the simple reason that the universe is nothing like a human made object or machine.
A further criticism of the Teleological Argument, again coming from Hume, is that even if we could validly reach the conclusion that there is a designer of the world, we would still not have sufficient information to arrive at the Judaic-Christian conception of God, i.e. an omnipotent, all loving and infinitely wise being. Hume used the analogy of the scales to illustrate this point, describing how if one side of a pair of scales is seen and observed to be out-weighed by an unseen quantity or object on the opposite side, all we can assert is that the unseen quantity is greater in mass than the seen quantity. We cannot assert the exact mass, size, shape, colour or any other attribute of the unseen object. For example, if the visible object weighs 10 Kg, all we can say with certainty about the obscured object is that it weighs more than 10 Kg.