Arguments from silence appeal to an absence of evidence regarding a particular claim. They’re common, but they’re notoriously weak. Literature on critical thinking regularly warns about their dangers and misuse. There’s even a saying used to combat them: “Absence of evidence is not evidence of absence.” In other words, just because you don’t know about something doesn’t mean it isn’t real.
Consider the following arguments:
- The Exodus never happened. There’s no evidence that it did.
- St. Paul doesn’t know about the Virgin Birth because he never mentions it.
- Jesus is just a Christian myth. He’s never mentioned by any first-century, non-Christian authors.
- If the papacy were true, it would be mentioned in the New Testament, but it’s not.
Arguments from silence rely on the silence of a source, which may be broad or narrow.
Our first argument—about the Exodus—does not specify a source and simply says there is “no evidence” for the event, but presumably this means that there is no archaeological or ancient literary evidence. Our remaining arguments do specify the sources that are supposedly silent: St. Paul; first-century, non-Christian authors; and the New Testament, respectively.
It’s important to realize what source is under discussion in an argument from silence, because the source may or may not be relevant to the claim being made. Arguments from silence can be put in a basic logical form:
Premise 1: If claim C were true, then it would be mentioned in source S.
Premise 2: C is not mentioned in S.
Conclusion: Therefore, C is not true.
In principle, there is nothing wrong with this type of argument. It’s a valid form of argument (known to logicians as modus tollens), so its conclusion will be true if its premises are true.
So why are arguments from silence considered weak? Because often one or both premises is or are doubtful or untrue. This means we can classify problems with such arguments by which premise is problematic.
First-premise problems
The problem may be that the first premise is false: It isn’t really the case that a particular source would mention something. Why should it? That’s the question that needs to be asked.
There is a chain of things that must to happen for an event to be mentioned in a source we have, whether the source is a single document or a collection by multiple authors, though here we will speak in terms of a single author to keep it simple.
First, the author of the source had to learn of the thing in question. If he didn’t know about it, he can’t mention it.
Second, the author must want to discuss it. The author needs a motive to mention what we’re interested in.
Third, there needs to be nothing preventing the author from recording it. Yet there often is. A subject might be embarrassing. It might be irrelevant or distract from the point he is trying to make. He may have limited room to write. Many things may stop an author from mentioning something, even if he had some desire to talk about it.
Fourth, the source must survive and be accessible to us. Yet most ancient sources have been lost.
Numerous things can prevent information about the past from getting to us, and it can’t simply be assumed that an author would mention it.
To establish that he would have, we need to first establish that (1) he would have been aware of the thing in question, (2) he would have wanted to mention it, (3) nothing would have deterred him from doing so, and (4) we still have the relevant part of his writings.
It often can be impossible to satisfy these conditions, and if you’re not 100 percent sure of the truth of the first premise, the best you can do is make a probabilistic argument, with the probability of the conclusion going down as confidence in the first premise goes down.
Sola scriptura
A central teaching in the Protestant community is that Christian doctrine needs to be formed sola scriptura (Latin, “by Scripture alone”).
This teaching holds that Scripture is sufficient to give us all the data we need for the doctrines we are supposed to believe, and so every Christian doctrine must be stated or implied in the Bible. Protestants commonly assume that God—as the ultimate author of Scripture—had the intention of providing us with the complete set of data needed for Christian doctrine in the Bible.
As a result, arguments from silence are common in Protestant theological and apologetic discussions: If a doctrine isn’t mentioned in Scripture, it is either false or something God doesn’t want us to believe.
It is difficult to underestimate the role that arguments from silence play in Protestant discussions. They may be applied in disputes with Catholics (e.g., where is the papacy, purgatory, or praying to the saints mentioned in the Bible?) or in intra-Protestant disputes (e.g., where is infant baptism, the Rapture, or perseverance of the saints mentioned in the Bible?).
Such arguments depend crucially on the initial premise of sola scriptura. But if God did not mean Sacred Scripture to be sufficient to tell us everything we need to know about doctrine—and instead intended it to be supplemented by apostolic Tradition—then these arguments from silence do not work.
It is important that people not assuming the Protestant viewpoint remember this when evaluating a doctrinal matter. The subject in question may not be mentioned in Scripture, or Scripture may not contain all the needed data. Instead, this data may be found in Tradition.
First-premise evaluations
How well do the arguments from silence we’ve considered fare in terms of their first premise?
When it comes to the Exodus, two reasons Egyptian literary sources might not mention it spring to mind. First, most Egyptian literature has been lost. Even in Egypt, papyrus can decay over time.
Second, when it comes to stone monuments, the pharaohs weren’t in the habit of recording everything that happened. They wrote about their victories on monuments to thank the gods and to announce their personal greatness, but they never record defeats. They would scarcely be likely to write about a successful slave rebellion on a monument!
Regarding St. Paul’s knowledge of the Virgin Birth, we know he wrote letters that no longer survive (he mentions some), so it’s possible that he wrote about it in those.
However, in none of Paul’s letters is he trying to give a biography of Jesus. Instead, he is dealing with doctrinal and pastoral problems in local churches. From the evidence at hand, it appears none had a problem with the Virgin Birth, so Paul had no occasion to mention it. We thus can’t infer that Paul didn’t know about it from the fact he never mentions it explicitly.
When it comes to first-century, non-Christian sources mentioning Jesus, the Christian movement began only partway through the century, and it was so small that most non-Christian authors either hadn’t heard of it or knew very little about it, giving them little reason to mention it. By the end of the first century, there were only a few tens of thousands of Christians out of the 60 to 75 million people in the Roman Empire.
Furthermore, most literature from this period has been lost, and Jesus could have been mentioned in numerous non-Christian sources that we no longer have. To the extent he isn’t mentioned in the surviving works, the silence is not surprising.
As for the papacy not being mentioned in the New Testament—to the extent that it’s not—the argument lacks force if sola scriptura is not true.
Second-premise problems
Arguments from silence also can go wrong due to problems with their second premises—the idea that a source doesn’t mention something.
First, we must deal with the issue of terminology. Language changes over time, and arguments from silence can go wrong when this fact isn’t recognized. When evaluating what a source says, we must understand the language and concepts in use at the time. We cannot insist that it use the terms we are familiar with.
For example, terms such as papacy, purgatory, sola scriptura, and total depravity are post-biblical, and it would be a mistake to insist on seeing these terms used in Scripture. Even if we were to assume sola scriptura, the question would not be whether these terms are found in the Bible but whether they reflect concepts that are.
Second, we must ask whether a source really is silent, and there are a range of possibilities.
It may be that the source does mention what we are investigating—even multiple times—yet the person mounting the argument from silence has not recognized it. In this case, the source is not silent at all.
On the other hand, there may not be an explicit mention of our topic, but it may be implied by one or more passages. In this case, the source’s silence is apparent rather than actual.
For example, the Trinity is not explicit in Scripture. There is no passage that says, “God is one Being in three Persons.” But there are multiple passages that—taken together—imply this.
Finally, it may turn out that the source does not state or imply what we are after, but it may contain information that is consistent with or suggestive of it. In this case, the source is only partially silent.
Second-premise evaluations
Our four initial arguments each encounter problems with their second premises.
Although Egyptian records don’t mention the Exodus, a monument known as the Merneptah Stele records a successful military encounter between Egyptian and Israelite forces, and it describes Israel as a nomadic people—as they were during the Exodus. Further, the stele dates from the time of the Exodus, and so Egyptian literature contains information consistent with and suggestive of the Exodus.
Paul does not mention the Virgin Birth, but he does describe Jesus as “born of woman” (Gal. 4:4). This isn’t conclusive, because the phrase could simply refer to a human being, but it is consistent with and possibly suggestive of a virgin birth.
The claim first-century, non-Christian sources don’t mention Jesus is simply false. The Jewish historian Josephus mentions Jesus twice, though one of the passages hasn’t been preserved in its original form.
And not only does the New Testament contain numerous passages illustrating that Peter had a special leadership role, three of the four Gospels contain passages in which Jesus gives Peter a special commission with respect to the other apostles and thus the Church (Matt. 16:17-19, Luke 22:24-32, John 21:15-17).
Silence by exclusion
Arguments from silence also may exclude relevant sources that aren’t silent.
Why focus only on Egyptian sources for the Exodus? There are good reasons pharaohs wouldn’t record it, but the Israelites would be very interested in discussing it, and they did! The Exodus is mentioned all over the place in the Old Testament. It’s a regularly recurring theme.
Concerning whether Paul knew about the Virgin Birth, we shouldn’t look only at Paul’s writings. The event is discussed prominently in two independent sources—Matthew and Luke—establishing that it was a common first-century Christian belief and thus one Paul likely knew about.
When it comes to mentions of Jesus, why draw an arbitrary line at A.D. 100 and dismiss sources after that? Jesus is mentioned by three Roman authors (Tacitus, Suetonius, and Pliny the Younger), all writing around A.D. 120.
Furthermore, why ask for non-Christian sources at all? The people most interested in Jesus were Christians, so their writings would be the most relevant ones for learning about him and his life. Others would scarcely have any interest in writing about him—at least while Christianity was small.
In each case, non-silent sources are being ignored, and often the most relevant sources. It is difficult to avoid the impression that those using these arguments have deliberately excluded the most relevant sources for purposes of making their argument seem stronger than it is.
Thus, another problem with arguments from silence is that they may consider the wrong sources.
Partitioned arguments from silence
A special case of this occurs in what we may call partitioned arguments from silence.
These happen when a person acknowledges that a source plausibly does mention a topic in one or more passages but then wants to partition these from consideration. He insists that there would be more passages mentioning the topic if it were true.
This is typically done by an appeal to the supposed importance of the topic. For example, a Protestant may argue, “Yes, Matthew 16:17-19 can be read as establishing Peter as pope, but the papacy is so important that we would expect it to be mentioned elsewhere.”
If one then points out that Luke 22:24-32 and John 21:15-17 also support the idea, these may be partitioned as well. In fact, no matter how many passages are brought forward, more may always be demanded.
From a psychological perspective, it is understandable that a person who is not convinced of a position will want more evidence than has been presented—especially if he is already committed to a contrary position. However, from an objective perspective, this kind of partitioning seriously undermines the argument from silence.
First, the tactic admits that the source plausibly is not silent at all!
Second, the assessment “But there should be more!” is entirely subjective, and in the heat of a discussion, the topic may take on an exaggerated importance in the person’s mind. It may seem highly important in the moment, but it may not be in the overall scheme of things.
Further, the tactic can be applied in any discussion—for one may always demand more evidence than one has been shown.
This is the case even when we are agreed that we have non-silent sources. A skeptic may say, “I don’t care that Matthew and Luke explicitly state that Jesus was born of a virgin. I want to see more evidence for this!” In fact, that’s the usual reason people want to see Paul mentioning the Virgin Birth in the first place, as Paul is allegedly writing earlier than Matthew and Luke.
Whether one partitions entire sources (Israelite literature, Christian literature, or Matthew and Luke) or just parts of sources (Josephus’s mentions of Jesus or Matthew 16:17-19), the tactic of silence by exclusion is yet one more reason why arguments from silence are notoriously weak and must be carefully evaluated.