God of the gaps
A God of the gaps argument is one that argues that since some phenomenon is unexplained, it must be due to God. It is also a form of non sequitur, since the hand of God is posited without proof and often with complete disregard to other possible explanations.
- "Scientists can't explain how life came to be. There must have been a god to create the first life form."
- "The Big Bang theory doesn't explain what caused the Big Bang. There must have been a god to set the universe in motion."
- "The bacterial flagellum is too complex to have evolved through natural means. Therefore, an intelligent designer must have been involved in its formation."
- "Even if the theory of evolution is correct, it doesn't explain how the first life form arose. Perhaps God's hand created life and set evolution in motion."
- "Scientists can't explain everything about how consciousness arises, therefore something divine must be at work in conscious beings."
Gaps are shrinking
A god of the gaps argument is an argument from ignorance: it boils down to "We do not know how X happened, therefore X was caused by a god." However, ignorance is never an argument for something. It merely means we do not (yet) know the cause of the phenomenon.
To see why this argument is a fallacy, we can consider similar arguments could have been made at different points in human history:
- 2000 years ago: "We do not know what causes lightning, therefore it must be a god throwing lightning bolts from the sky."
- 1000 years ago: "We do not know what keeps the planets in their courses. There must be angels pushing them along."
- 500 years ago: "We do not know what causes diseases, therefore they must be punishments from God."
- 200 years ago: "We do not know how the many species of plants and animals could have appeared, therefore God must have created them."
- 100 years ago: "We do not know how the universe started, therefore God must have done it."
- 60 years ago: "We do not know how genes are passed from parent to child, therefore traits must be imprinted upon the soul."
As new explanations emerge, the gaps in our knowledge shrink, leaving less and less room in which to fit a god. Since human knowledge keeps growing all the time, it does not seem like a safe bet to assume that any given gap will remain one for very long.
An insufficient explanation
Another objection can be made to the argument's means of ignoring the question it originally intends to answer. For example, answering "What caused the big bang?" with "God did it" still does not answer the question of origins, as the god inserted into the gap still requires an explanation.
How, not What
Theists are frequently intolerant of scientific concepts that seek to provide naturalistic explanations. It is not difficult to reach a "compromise" where the theist adopts the full scientific explanation without challenge. By asking the theist "How did God do this?", the theist generally becomes receptive to the scientific explanation.
By presenting arguments in a manner that theists can accept, they gain knowledge, which is always poisonous to theistic belief.
The real question isn't "Is this possible?" it's "Is it probable?" We should be concerned with whether or not a thing is actually true or likely true - not whether it's possibly true.