Proponents of Intelligent Design (Creationism) often argue that fine tuning, which is a rather inaccurate term for the physical constants of the universe, must have been finely tuned by a "designer" and therefore denote a higher intelligence, or in their minds, [G]od.
But to jump from physical constants to an intelligent creator being (of some sort) is a logic leap which betrays a failure in their line of reasoning. Let me explain by way of a thought experiment.
Let me give three sets of random numbers. Now, for the sake of argument, let's assume that each of these numbers represent the physical constants of three separate universes. Fair enough? Good.
Universe A 568723410048009
Universe B 334223112556778
Universe C 111111111111111
My question is this, which universe is the so called "finely tuned" universe?
You see, fine-tuning isn't something which happens to the universe. The physical constants just are--as such discovering the physical constants is merely an observation which doesn't preclude the conscious act of design. The numbers are just what they are. The fact that we can discover these physical constants and measure them means that whichever set of numbers we observe just happens to be right for life to exist.
In my thought experiment above--all three examples are right for life, because no matter which physical constant you are looking at, the fact that you can observe it means that it allows for the right conditions for life, like you, to evolve.
Yet all of these physical constants were just randomly generated. Not by me, but by an unthinking computer. So there was no sense of "tuning" these numbers to fit my expectations or desires for there to be life. They just popped out of thin air.
Suffice to say, IDers are wrong to assume that fine-tuning is evidence for God, or any transcendent intelligence of any kind. Fine-tuning is not (I repeat... not) evidence for God. The physical constants of the universe are just sets of numbers based on what we measure and observe. We just so happen to inhabit a universe with a set of physical constants which allows for the sustainable existence of life (which is why we can observe it in the first place). It's that simple.