Monday, September 27, 2010

On being ad hoc

Last week, when I wrote briefly about Jason Lisle's new paper in ARJ on starlight and time, I suggested that his explanation of other appearances of age was ad hoc. Here's what he wrote:
We note that the ASC model only accounts for distant starlight and other earthward-directed phenomena that move at nearly the speed of light (such as neutrinos). It has been suggested that other celestial phenomena require billions of years: collisions of galaxies, jets of material from active galactic nuclei (AGNs), etc. However, I do not believe this is so. It seems to me that the mature creation argument works quite well on distributions of matter. Unlike light, the supernatural creation of matter in a specific configuration does not undermine any precondition of intelligibility; nor do we have biblical information that would be contrary to the idea that God may have created the matter in the universe very close to its present location. So, we should consider the possibility that galaxies currently in collision may have been created in collision.
One reader didn't quite understand how that was ad hoc. I think that's ad hoc because it doesn't really explain why there are two galaxies that appear to be in collision (like these). Lisle suggests that maybe God just wanted it to look that way.

Here's the weird part, though. What about the light-in-transit explanation? What if there aren't really any stars out there? What if God just created light on the way to earth to make it appear as though there are stars out there? Lisle doesn't like that explanation because it makes our senses unreliable. As he wrote,
The light-en-route model requires that events we observe beyond about 6,000 light years (which covers the overwhelming majority of the universe) are fictional, and thus our senses are not reliable for those distances. If we cannot believe our eyes for 99.9999% of the universe, then why should we trust them for the other 0.0001% that is nearby?
OK, that's great. So for certain configurations of light, Lisle believes they convey real information about the origin of that light (i.e., that there really are stars out there). Fine. But why then reject the exact same explanation for configurations of matter? If God didn't just make light to look like it came from stars that aren't there, why did God make galaxies look like they are colliding when they really didn't?

I guess that's the source of my unease about this whole thing. Lisle could be right about his explanation being biblical, and I guess he could be right about the speed of light (what do I know, I'm a biologist?). But even if he is, would it matter? As he himself concedes, his argument is not intended as a cosmogony, and it does not explain other indicators of great age. Perhaps most importantly, why the double standard? Why does light tell us something true about its origin, while matter does not?

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