Huge, Flying Rocks In Space vs. Carl Sagan’s Dragon In The Garage

Posted in Astronomy, Logic, Philosophy, Science on  | 7 minutes | 27 Comments →

So, seasoned readers and veterans in philosophical, scientific, or religious debate are surely familiar with the astronomer Carl Sagan's famous and hypothetical dragon in the garage argument:

"A fire-breathing dragon lives in my garage."

Suppose I seriously make such an assertion to you. Surely you'd want to check it out, see for yourself. There have been innumerable stories of dragons over the centuries, but no real evidence. What an opportunity!

"Show me", you say, and I lead you to my garage. You look inside and see a ladder, empty paint cans, an old tricycle – but no dragon.

"Where's the dragon", you ask.

"Oh, she's right here", I reply, waving vaguely. "I neglected to mention that she's an invisible dragon".

You propose spreading flour on the floor of the garage to capture the dragon's footprints. "Good idea", I say, "but this dragon floats in the air". Then you'll use an infrared sensor to detect the invisible fire. "Good idea, but the invisible fire is also heatless", I say. You'll spray-paint the dragon and make her visible. "Good idea, except she's an incorporeal (bodyless) dragon and the paint won't stick!"

And so on. I counter every physical test you propose with a special explanation of why it won't work.

Now what is the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all? If there's no way to disprove my contention, no conceivable experiment that would count against it, what does it mean to say that my dragon exists? You're inability to invalidate my hypothesis is not at all the same thing as proving it true. Claims that cannot be tested, assertions immune to disproof are veridically worthless, whatever value they may have in inspiring us or in exciting our sense of wonder. What I'm asking you to do comes down to believing, in the absence of evidence, on my say-so.

With all due respect to the late Mr. Sagan, although it contains an eminent truth, this argument is also eminently bunk. Now I agree that the inability to invalidate a hypothesis does not prove a competing hypothesis true. However, the following line is correct only in the extremely limited scope
of validating a scientific hypothesis (and even then can break down):

Claims that cannot be tested, assertions immune to disproof are veridically worthless..

I hear too many skeptics and atheists cite this passage
foolishly thinking it somehow counters religious claims or the
existence of God. There are several reasons this is incorrect, but first let me counter with my own little story, custom-tailored to address Mr. Sagan's area of expertise: Astronomy.

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