Do extraordinary claims require extraordinary evidence? Let’s pick apart this age old saying.
“Extraordinary claims require extraordinary evidence.”
This quote was made by astronomer Carl Sagan in the late 70s. The phrase is primarily based on probability, which is to say the less probable something is the stronger the evidence needed to offset its improbability. I don’t find this approach practically useful, however, and this will become apparent if we begin to deconstruct the phrase piece by piece.
It seems simple enough, but what is “evidence” and how are we to define it in every day life? We live in a world governed by physical law, otherwise known as the law of cause and effect. There is nothing in this universe that happens without a cause. Branches do not sway without the wind, food does not cook without a fire, and everything we do we do because something has caused us to (I am writing this because I see Sagan’s quote being reused, and it is being reused because it is popular, and it is popular because….etc, etc.).
Evidence is the sensory manifestation of cause and effect. If you notice a footprint in the mud that is evidence of something having walked through it. Something caused that footprint and even if we do not immediately see the cause we see its effect and can determine, based on the information we can gather from it, whether it is human or beast.
If evidence is effect, whether brief or enduring, then placing it upon a spectrum of ordinary to extraordinary makes no practical sense. If we base extraordinary claims on probability, then extraordinary evidence is a misnomer. If we return to our example of a footprint in the mud, probability could go both ways. It could be a popular hiking trail or it could be a random slice of uninhabited bush. Either way we come to the same conclusion. We do not need anything more than a footprint in the mud to determine that something caused it because we have an idea of what the cause is.
How about an active volcano and a volcano that has been dorment for thousands of years? It is easier to believe that Mount Vesuvius is erupting than Mount Kilimanjaro erupting. However, if I see lava shooting up out of the surface of Kilimanjaro I’ll have known it has woken up because that is an effect I associate with a cause I know, that being an active volcano.
In conclusion, we only need to see an effect relevant to what we know of its cause. I know the nature of an active volcano so I do not need to see more than that to determine the truthfulness of Kilimanjaro erupting. The terms extraordinary and ordinary have no relation to the nature of evidence as cause and effect. Sometimes we may need to see more examples to form a clearer, more certain picture, but we never call for something “extraordinary” because it is impossible to practically determine what such a thing would be unless we veer into the realm of madness (should Kilimanjaro suddenly start speaking and calling you by name? “Bill, I am going to erupt!”). Sayings such as Sagan’s have no practical functionality unless we redefine evidence until it becomes something we no longer recognize.
The scope of this article is not to provide evidence for God, for such a thing is nebulous in the realm of natural science, but to think about the nature of God more deeply.