The narwhal is occasionally known by its nickname "the unicorn of the sea", owing to its large tusk, resembling the horn of a unicorn. Imagine, for a moment, you find someone who believes they are as fictitious as their namesake. "Narwhals are just a myth", they declare. You happen to know a museum with an actual narwhal tusk on display. With the tusk before their eyes, they declare "that doesn't prove narwhals still exist."
This is an example of the "shifting the goalposts" fallacy, in which one intentionally changes the standard of evidence during the course of debate. This can take two forms: An implied standard of evidence, which is later rejected, or a pre-agreed acceptance of evidence that is later rejected.
The narwhal example takes the first form. In this case, the skeptic made an absolute statement, "narwhals are a myth". This absolute claim implies any physical evidence of narwhals, such as the tusk in the museum, should disprove their claim. However, this evidence is dismissed when the skeptic revises his original statement. "Narwhals are a myth (i.e. do not exist)" now becomes "narwhals do not still exist."
This is a common fallacy in religious debate. A recent example, similar to the narwhal analogy, can be seen in a viral video entitled "1 Atheist vs 25 Christians (feat. Alex O'Connor) | Surrounded". In this video, atheist apologist Alex O'Connor, also known as "Cosmic Skeptic", makes four claims, and discusses them with Christians. One of those claims is "Jesus never claimed to be God".
With O'Connor having laid down his claim, the first Christian approaches him, and after a friendly handshake, he asks "I'm curious, are you including the book of John?" O'Connor replies "So, I think that the book of John is probably the least historically reliable in this case. So I'm talking about the historical Jesus. I do think that there are a number of instances where Jesus appears to claim to be God in John's Gospel, but even if we think that He actually said that, I still think that there's reason to believe that He wasn't claiming to be God in the sense of being identical with Yahweh."
Note how O'Connor's original statement "Jesus never claimed to be God" is an absolute claim about Jesus, implying if we can find evidence that Jesus did claim to be God, the claim is disproven. However, although O'Connor acknowledges the book of John does contain instances where Jesus appears to claim to be God, he amends his original statement, claiming "I'm talking about the historical Jesus". He gives no reason for dismissing the book of John as historically unreliable, or for distinguishing between "the historical Jesus" and the Jesus described in John's Gospel (which is a primary historical source on Jesus), but he expects his audience, and his opponent, to take that seriously. Because O'Connor amended his original statement in order to arbitrarily dismiss evidence after it has been presented, he has committed the shifting the goalposts fallacy.
Another example of the shifting the goalposts fallacy is a story Mike Winger tells about when he told his Roman Catholic friend "the Bible says "For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast." The Roman Catholic responded "Mike, that would be scary if it was in the Bible." So Mike showed him Ephesians 2:8-9, which says those exact words. The Roman Catholic replied "I don't think it means what you think it means."
By saying it would be scary if it was in the Bible, the Roman Catholic implies such a verse would provide a challenge to his beliefs. Upon seeing it in Scripture, however, his problem switches from "it's not there" to "it's there, but you're not interpreting it right".
As the shifting the goalposts fallacy is a common one, it is best dealt with pre-emptively. That is, before presenting evidence, ask your opponent how they might deal with such evidence if it is presented, then "lock them in", so to speak. By this, I mean if they give one answer, but try a different one after the fact, make them justify their new answer. "You said if this evidence was presented, your position would be refuted. Now that this evidence has been presented, you have not conceded. Please explain why the evidence is no longer acceptable to you."
Failing the pre-emptive approach, the fallacy is still fairly easy to point out. Begin by identifying the original claim, and how it implies a criteria for refutation. Bonus points if your opponent has already stated they would accept a certain piece of evidence. Then expose the shift. This is best done in question form, as it requires your opponent to really think about the answer.
The shifting the goalposts fallacy, at its core, suggests a higher commitment to one's position than to the truth of the matter, and a stronger desire to win a debate than to actually adapt one's views to the truth. By learning to recognise and counter this fallacy, both in others and in ourselves, we contribute to more fruitful discussions.
AI usage
AI was used in the following ways to produce this article:
1. The creation of the header image.
2. Refining the narwhal analogy to ensure it fits the criteria of shifting the goalposts.
3. Scanning the entire article for typos.
4. Minor tweaks to the wording of various sentences, reducing redundant phrases.
5. Suggestions for a concluding paragraph, preventing an abrupt ending. I opted to merge options 2 and 3, both of which focused on the intellectual honesty aspect of the fallacy.