Thursday, May 21, 2009

What if Scientists were Wrong?

Scientists generally explain the origin of life on Earth - including all the complex biological features we see - in terms of physical chemistry, genetic variation, natural selection, and so on. But many people reject these explanations, and believe that "intelligent design" (ID) is the best explanation for how life came to exist on Earth.

One problem with this is that even if our current scientific understanding of life origins was somehow shown to be wrong, the best explanation remaining still wouldn't be "intelligent design". Instead, the best alternative explanation (the one that fully accounts for what we see while making the fewest unsupported assumptions and leaving the fewest questions unanswered) would be that living things on Earth are the descendants of living things elsewhere.

This idea that our ancestors were extra-terrestrial life forms - let's call it ET-ancestor theory - would explain why there is life on Earth, but it really isn't a very good theory. For one thing, we have no evidence that alien life forms have ever existed, much less that we are their offspring. Moreover, this idea would only account for how life came to exist on Earth, and not how life began in the first place. Still, if our current scientific theories were discarded, this would be our best explanation, because other possible explanations would be even worse.

For example, we might theorize that rather than being the descendants of extra-terrestrial life forms, we are the products of their advanced bio-engineering capabilities. This idea (call it ET-engineer theory) requires not only that we believe in extra-terrestrial life, but also that these ETs were highly skilled bioengineers. Since we also have no evidence that this additional assumption is true, this theory is even less likely to be correct than ET-ancestor theory. And of course this theory also doesn't explain how life began in the first place.

Another theory that would be worse still would be this: Imagine instead of an extra-terrestrial life form - something alive like us with some sort of complex physical body - there existed something completely different that could still somehow do what a human bioengineer does. What sort of entity this might be is unclear, except to say that it is a non-biological intelligent "agent". In other words, this theory is talking about something sort of like a person, but without a living body - maybe like a ghost or a spirit or a god - which somehow engineered living organisms (call it non-living engineer theory).

This theory is more far-fetched (that is, removed from our experience-based knowledge) than either ET-engineer theory or ET-ancestor theory: To accept this non-living engineer theory, we not only have to believe in something that existed prior to life on Earth that used advanced bioengineering abilities (rather than good old biological reproduction) to create terrestrial species, but we also have to believe in something that wasn't itself alive but still had all of the mental and physical powers of living bioengineers (and then some). This speculation is contrary to our experience, since in our experience only living, embodied organisms have these sorts of abilities.

And of course just like the other theories that fail to explain how our hypothetical alien ancestors (or inventors) came into existence, this one can't explain how this hypothetical non-living bioengineer came to exist either.

What about "intelligent design" theory? ID says that life arose because something engineered us (rather than because something simply gave birth to us, or because life arose by any other means) but ID doesn't say if this engineering entity is supposed to be a living organism or something else. In other words, ID is nothing but a combination of the ET-engineer and non-living-engineer theories. But the result of combining two bad theories is just another bad theory, and neither of these two engineering theories is even as good as ET-ancestor theory - which isn't very good to begin with.

So even though ID isn't supposed to be about the identify of the Designer, once we look at the only two logical possiblilities (the Designer of Life was either itself a life form itself or it wasn't), it seems obvious that ID is a particularly poor candidate for explaining life on Earth. Maybe our understanding of abiogenesis and evolution is substantially correct already, and maybe it isn't, but just because one theory is wrong doesn't mean that either alien life forms or God becomes the default explanation that we should accept. There may be characteristics of the universe that we do not yet understand which make life probable or even inevitable, but have nothing to do with a conscious designer dreaming up new ways to build flagella, blood clotting cascades, and aardvarks.

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