A note on design: What's fine-tuning got to do with it?

We have known for a long time that there is complex, intelligent life. More recently we have discovered that the physics of our universe is fine-tuned so as to allow for the existence of such life. Call these two observations the Old Datum and the New Datum, respectively. Our question here is: once we know the Old Datum, does the New Datum provide additional evidence for the design hypothesis? I will argue that it does not. Thus, there is an important sense in which the much-touted fine-tuning of physics is irrelevant to debates about design. Informally put, the version of the design argument that concerns us here runs as follows. Begin with the observation that certain parameters in the laws of physics and the initial conditions of our universe are fine-tuned so as to allow for the existence of intelligent life. Out of the range of values these parameters could have taken, only a small portion yield a universe with enough complexity to ground intelligent systems, and yet the actual values fall in that small range.1 Now consider that such fine-tuning is to be expected if the universe was created by a designer of the sort typically postulated in western monotheistic traditions. Such a designer wants to create intelligent life, and can thus be expected to set the relevant values so as to allow for intelligent life. But if the universe was not created by such a designer, there is no reason to expect these values to be as we find them. Indeed, it seems much more probable that the actual values would fall outside of the small range necessary for intelligent life.2 So the fact that fine-tuning obtains favours the design hypothesis over its negation.