Evolution and gravity have a lot in common. We experience them every day, yet we don't fully understand how they work. That's why both are under investigation by scientists. Both phenomena have been misused to bring great suffering to humanity: gravity is what makes bombs fall on cities and Social Darwinists have attempted to argue against welfare, healthcare and for euthanasia. We can use mathematics to predict how gravity and evolution change the systems in which they act. This is also where the differences start. We cannot tell if our own solar system is stable, or if Mars will slam into us at some point in the future. The mathematics we have in quantitative genetics are comparatively simple and work well. In fact, our understanding of the mechanics of gravity, i.e., how mass bends space-time is - compared to the mechanics of evolution - extremely poor. While we know that mutation, selection and a bunch of other factors play a role and how they interact, we know next to nothing of how gravity acts to exert attraction, i.e. bends space-time. To understand what provides particles with mass, physicists have built the Large Hadron Collider in Geneva, the largest and most complex experiment in the history of humanity. So with evolution and gravity we have two readily observable processes, where we know a lot about one and comparatively little of the other.
Interestingly, to my knowledge, only once has there been an alternative explanation of gravity offered from non-scientists to the scientific community, in a spoof news article from the satirical newspaper The Onion: Intelligent Falling. In contrast, for the much better understood phenomenon, evolution, there is a endless stream of non-scientists coming up with similarly funny alternatives, such as the various forms (intelligent design, young earth, etc.) of creationism. Only that these alternatives aren't meant as spoofs at all, despite being scientifically even less valid than intelligent falling. One really needs to let that sink in: because we know less about how gravity works than about how evolution works, intelligent falling is more difficult to rule out than creationism. Yet, creationism receives all the media attention and intelligent falling very little. Why is that?
Mike, the mad biologist has a recent blog post that explained a lot to me. In it, he quotes a New York Times article from 2005: "They have mounted a politically savvy challenge to evolution as the bedrock of modern biology, propelling a fringe academic movement onto the front pages and putting Darwin's defenders firmly on the defensive." This is what makes the difference between the population at large and the scientific community. Everything is political in public. Even science. If the Discovery Institute were launching a politicaly savvy attack on gravity, would the Large Hadron Collider be on the defensive? Would intelligent falling be on the cover page of major newspapers in the US? Reading Mike's blog post, I have very little doubt it would.
The more interesting question is, what do you do about it? I think the issue is related to the problem of multiplying inane diclaimers such as these: In a society that needs such disclaimers, intelligent falling has an equally good chance chance of becoming mainstream as creationism. In a society where the obvious is commonplace, neither creationism nor intelligent falling will waste anybody's time.