To quote William Paley:
In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that, for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer I had before given, that for anything I knew, the watch might have always been there. (...) There must have existed, at some time, and at some place or other, an artificer or artificers, who formed [the watch] for the purpose which we find it actually to answer; who comprehended its construction, and designed its use. (...) Every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater or more, and that in a degree which exceeds all computation.
I think this is the gist of it :
1. When I see a watch I know intuitively that it was made by a human being.
2. Why do I have this intuition? The complexity of the watch is that which intuitively suggest an intelligent designer.
3. Similarly the complexity of nature should intuitively suggest to us such a designer.
4. Since this designer is clearly NOT a human therefore it must be someone else i.e. God.
Ok now the problems:
The first proposition is sound.
The second proposition:
The complexity of the watch is that which intuitively suggests an intelligent designer. Who says that it is the complexity of the watch which suggest to me that it is made by an intelligent designer. Perhaps it is my prior experience with watches and things crafted by man? Would a cave man instantly recognize the watch as intelligently and purposefully designed? Would an alien? I'm not sure...
The third proposition:
Similarly the complexity of nature should intuitively suggest to us such a designer. A few problems: Firstly if it's so intuitive why the need for the watch analogy in the first place? I should just KNOW in a flash of intuition! Maybe it's my תאוות for sex and drugs which are blinding me and the watch will knock some sense into me....
Wikipedia suggests that the watch is merely a rhetorical device in which case the argument boils down to: "You know nature is designed because it's complex. THE END" which is a blatant non-sequitir. One has to explain WHY complexity automatically suggests design...
But another question! If everything is designed either by God or Man then how is it that it is so easy for Paley, in the quote above, to distinguish between rock and watch. According to his
own logic I should NOT be able to distinguish between the two because they are BOTH products of design. Either God's or man's. Have you my dear theist, ever seen an un-designed thing? You have? Then you've seen something not designed by God? A little kefira-dick don't you think?
I suppose you could say maybe that only organisms are designed. (Even though that would be kefira-dick) You have to admit they are more complex than rocks....
In which case the argument is I can intuitively discern watches from rocks
the same way as I can discern kangaroos from rocks.... I guess that could be sound if there weren't all the other objections...
The Fourth Proposition:
Since this designer is clearly NOT a human therefore it must be someone else i.e. God. Or martians.
"Silly, atheist! Where did the martians come from!?" "hmmmm maybe from the same place God came from...."
Also - how do we know the designer is not a human? What in our intuition allows us to discern between man-made design and God-made design? In fact if we take the analogy seriously it is actually suggesting that nature shows signs of being
man-made not God made. We simply have no rock stamped MADE BY GOD to compare nature to...
I guess you could say because we know from
elsewhere that man doesn't know how to manufacture orangutans...
AND FINALLY:
Intuition is sometimes rubbish. Humans see designs in french toast, clouds and ink splotches.... Wouldn't put too much faith in it...
The watchmaker argument is an appeal to emotions, an elegant statement about the complexity of nature which some cannot but attribute to God. But it is not logic nor should it be presented as such. To stand in awe of the universe and see a maker behind it is fine. However to call that science or logic is just incorrect.
Read the Wikipedia article for a fuller discussion....