What would you think if someone claimed that an invisible dragon lived in his garage? What about someone who claimed that an invisible teapot orbited somewhere between Earth and Mars?
The following are two great analogies, one about invisible dragons, and the other about an orbiting teapot, that I often think about when people make remarkable claims without any evidence.
The first is "Carl Sagan's Dragon" analogy, from his book The Demon-Haunted World, in which he imagines himself having a conversation with the reader following his remarkable announcement that a fire-breathing dragon lives in his garage:
"Show me," you say. 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."
You'll spray-paint the dragon and make her visible.
"Good idea, except she's an incorporeal dragon and the paint won't stick."
And here is Bertrand Russell's "Orbiting Teapot" analogy:
Many orthodox people speak as though it were the business of the skeptics to disprove received dogmas rather than of dogmatists to prove them. This is, of course, a mistake. If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in a elliptical orbit, no one would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it would be intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense.
What are we to make of such arguments?
1. The fact that we cannot disprove the invisible dragon and orbiting teapot, does not mean that it's reasonable to think they exist. To say, "Well, you can't show me any evidence that it DOESN'T exist," is not a convincing argument that it does. Remember, it's impossible to disprove nonexistent things include Loch Ness Monsters, fairies, and invisible pink unicorns. But that is no reason to suppose they exist.
2. The fact that we cannot disprove the invisible dragon or orbiting teapot, does NOT make it UNREASONABLE to believe that they DON'T exist. It is reasonable to measure out belief according to the level of evidence.
3. Richard Dawkins, in his book The God Delusion, makes the point that even though we cannot disprove Russell's orbiting teapot (or Sagan's dragon), this does not make their existence and nonexistence equiprobable. Or in other words, it's unreasonable to think there's a 50:50 chance of invisible dragons existing. The probability of such a dragon or teapot existing is much, much less than the probability that they do exist.
4. Finally, Bertrand Russell makes a crucial point: The onus is on the claimant to support their claim with good evidence. William Kingdon Clifford made the point (perhaps a bit too strongly) that "It is wrong always, everywhere, and for everyone, to believe anything upon insufficient evidence." Perhaps Clifford used too many superlatives, but the point is that we should have good evidence for what we purport to be true. In these examples, the initial assumption, or null hypothesis, is that the dragon or teapot do NOT exist. In order to disprove the null hypothesis (that invisible dragons and teapots don't exist), evidence needs to be found to support the notion that they DO exist. Without such evidence, we fall back to where we started: with no reason to suppose an invisible dragon exists or that a teapot is orbiting somewhere between Earth and Mars.
The relevance of these analogies to God's existence is not difficult to figure out. However, some will argue that the analog is not a good one. Belief in God, they say, is not like belief in invisible dragons or orbiting teapots since God created the universe, God gives life purpose and meaning, God is responsible for morality, or that life without belief in God is painful and pointless.
However, these justifications are not evidences for God at all. Saying that I really, really, really need to believe in God - for whatever reason - is not evidence, but merely opinion; sincere opinion to be sure, but misguided opinion since many many people find purpose and value in life, rational explanations for the universe's origins, and reasons to live moral and fulfilling lives without God (even though they might at one time really believed that it was impossible not to). These are simply assumptions, and that which is freely assumed can be freely denied.
In summary, the God hypothesis, to be considered a viable hypothesis, needs evidence to support it. God is just as invisible as both the dragon and teapot, nobody has seen God (at least there has been no sightings that can be verified for accuracy), we never hear from him, we can never touch him as it is written the Doubting Thomas did, nor can we observe anything God has made that cannot also be explained in natural ways more parsimoniously.
It is either as Nietzsche wrote that "God is dead," or else he was never around to begin with, but is just an invention of the human mind. Either way, we are alone on his pale blue dot; orbiting a medium size Sun; in just one of billions of galaxies; with nobody except for ourselves, our families, our communities, and other human beings to take care of ourselves.
And that's just fine with me.