Question

Appeal to Ignorance (argumentum ad ignoratiam) An appeal to ignorance proposes that we accept the truth of a proposition unless an opponent can prove otherwise. Thus, for example: • No one has conclusively proven that there is no intelligent life on the moons of Jupiter. • Therefore, there is intelligent life on the moons of Jupiter. But, of course, the absence of evidence against a proposition is not enough to secure its truth. What we don't know could nevertheless be so. This page describes different types of irrelevance and provides several examples of each .

In your own words answer the following questions for two of the examples. Why is the particular argument irrelevant? Why would someone make such an argument? If you were presented with this argument, how would you respond? Is the argument salvageable (can it be modified to make it more reasonable)?

Answer 1

This particular argument is irrelevant because it presents a type of false dichotomy, that is, if there is no intelligent life on Jupiter, it should be proved otherwise one should agree that there is intelligent life in Jupiter. In this type of reasoning, a third option is excluded which is that the current status is unknown because there hasn’t been any sufficient investigation. Individuals are likely to make this argu in that it excludes a third option, which is that there may have been an insufficient investigation, and therefore there is insufficient information to prove the proposition be either true or false.

This argument is often made when one attempts to shift the burden of proof, that is, the obligation to provide sufficient evidence for one’s position. If I were presented with such an argument, I would retort by pointing out that position is not dichotomous and that a fair conclusion can be made only after sufficient investigation has been complete. To make the argument salvageable, I would change the conclusion to ‘Therefore, it is probable that there maybe intelligent life on the moons of Jupiter.”