Sometimes the jokes write themselves. From today's student newspaper on my campus:
Second, they deny that life begins at conception. Every human whether alive or aborted, has been conceived. This first step in life’s process cannot be skipped, if it cannot be skipped and it’s the first step, then it must mean that it’s important and that it’s the beginning. Life begins at conception!
Welcome to the world of the post hoc fallacy. A biological process (sperm meeting egg) precedes another (fetus developing into a viable human life) therefore they are one and the same. Like how eating precedes shitting, and therefore eating is shitting.
Post hoc fallacies are among the oldest flaws in human reasoning, dating back to the days when cavemen banged on drums to make the sun come up. Every morning was a sign that it was working. A post hoc fallacy is any argument that looks at two events in a timeline and assumes that the earlier is either causal to or an integral part of the latter.
I hesitate to play the slippery slope game, but indulge me for a moment as I extend the reasoning used in the example above. We can't have life without conception, so conception is life. Well, we can't have conception without sex. Does life begin at sex? We can't have procreative sex without a male and female meeting one another. Does life begin when they meet? Men and women don't meet each other unless they make an effort to socialize. Does life begin when you decide to go to a party on the weekend?
I'm getting a little ridiculous here but not much more ridiculous than any other post hoc argument. Things that happen in a sequence are not necessarily causally related, and things that are causally related do not magically become the same thing. I wonder if it ever occured to the "Life begins at conception!" crowd that many people are not persuaded by the argument because it makes absolutely no sense. No, it's always that we liberals are misguided, uninformed, or wicked sodomites who hate Jesus. Demonizing one's opponents ("Anti-life!") because they refuse to be persuaded by fallacious arguments is…well, that's just the greatest recipe for political success I've ever heard. Good luck with that.