Shhhh! Do you hear that? That’s the sound of today’s logical fallacy: the argument from silence! Similar to the fallacy of an appeal to ignorance, the argument from silence is a fallacy of weak induction that treats the absence of evidence as evidence itself. This logical fallacy essentially takes an appeal to authority and flips it around. The appeal to authority says that because an authority A says x, then x must be true; the argument from silence says that because an authority A didn’t say x, then x must be false. In effect, the silence of the authority regarding some particular claim is taken as evidence against the claim itself.
On the surface such an argument may seem silly, but these types of arguments are in fact all too common, especially in regards to historical studies. For example, someone might say that Thomas Jefferson never wrote about an affair with his slave Sally Hemmings, so it must not have happened! But this is a fallacy. Jefferson’s silence is taken as evidence against the claim of an affair, but a lack of evidence here is not evidence itself. As Peter Kreeft explains, “When a speaker or writer is silent about x, we cannot conclude that he does not believe in x, or that there is no x.”¹
However, to complicate things a little further, unlike the appeal to ignorance, the argument from silence is not always fallacious and can sometimes even be a good argument. But how do we tell the difference between a good argument from silence and a bad one?
The first thing to note is that arguments from silence (even the good ones) are always at best weak and inconclusive; they cannot reach definitive conclusions by themselves. As such the best an argument from silence can hope to provide by itself is circumstantial evidence.
In history, the question has to do with the weight of the argument from silence, particularly when a writer fails to mention a putative event or fact that should have been known to him. Such arguments from silence are, as a rule, quite weak; there are many examples where reasoning from silence would lead us astray.²
Second, similar to the appeal to authority, the strength of an argument from silence depends largely on the strength of the authority in question and specifically what we might expect that authority to say. For example, would we really expect Jefferson to write about an affair with his slave? Considering the taboo nature of such a claim in Jefferson’s time, silence is actually what we might expect if the claim were true.
To illustrate the difference, consider this example. Let’s say you want to buy a used car from an ad and are concerned about hidden engine problems. You might say to yourself, “The seller didn’t mention any engine problems in the ad, so the engine must be fine.” This would be a fallacy. The seller (like me) may not know anything about engines, and he may not mention it even if he did! However, you take the car to a trusted mechanic who says the engine looks fine and doesn’t mention any problems. The silence of the mechanic would be good evidence in favor of a problem-free engine because if there were any problems, a good mechanic would be expected to find it and would have no reason to hide it from you.
Arguments from silence are some of the most common arguments used by skeptics to cast doubt on the Bible, and most examples fall far short of good arguments. Here are some examples of this fallacy at work.
One of the most common arguments from silence is the absence of explicit references to Israel and the events of the Exodus in ancient Egyptian historical records. Some historians, therefore, conclude that the Exodus must never have happened. However, it is certainly possible that the Egyptians might have had good reasons not to reference such an embarrassing course of events. It is also possible that the record of these events has not yet been discovered or was not as well preserved as other records. At best this argument from silence is only circumstantial and not a good enough reason to disregard the testimony of the Bible.
Another similar example is that few ancient Roman historians mention Jesus of Nazareth, so some conclude that Jesus must not have existed at all! But would we really expect Roman historians to include extensive reports of a remote Jewish teacher who had no significant impact on Roman politics during his lifetime? In fact numerous religious sects existed during Roman times that are never mentioned by Roman historians, and Jesus’ followers had virtually no impact on Roman history until centuries later. We should not be surprised that ancient Roman historians may have completely ignored Jesus of Nazareth.
Yet another example is the fact that Paul never mentions the virgin birth of Jesus in his epistles, and thus some conclude that Paul must not have known about or believed in the virgin birth and that this must have been a later invention. But why would we expect Paul to mention this specific detail? Was the virgin birth so relevant to Paul’s message that it would have been ridiculous for him not to include it? This would be a difficult case to make! It is much more likely that Paul knew a great deal about Jesus that he did not include in his letters, possibly including knowledge of the virgin birth.
After looking at the examples above, hopefully it’s clear that it can sometimes be a fine line between a good argument from silence and a bad one. Here are a few key questions to ask yourself that might help you to avoid slipping into a fallacious argument:
If you answered “no” to any of these questions, you might have a fallacious argument from silence. But even if you answered “yes” to all of the above, remember that even a good argument from silence is only circumstantial at best, and thus it is usually a weak argument that should be treated in most cases as inconclusive or uncertain when no other corroborating evidence is available. As a rule, more weight should always be given to what is actually said rather than what is not.
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