When the word testimony is brought up most people’s minds will immediately be brought to a court room scene, or to someone bearing witness to some religious experience.  A witness in the box stands in front of the court and gives their eyewitness testimony as part of the evidence for either the prosecution or defence.  Testimony is more than that though, testimony is the act of one agent passing on information to another agent through a speech act alone. 

For example, Person A arrives at the bus stop and asks person B, who is already waiting at the bus stop, whether the bus has gone yet.  Person B responds by telling Person A that it has not, and that they too are waiting for the bus to arrive.  Person A then takes their place at the bus stop and waits for the bus along with Person B, taking Person B at their word.  Another example of testimony is something like Person D telling their friend Person C what they had gotten up to the previous night, perhaps they were down the pub, or playing video games, or at the cinema. 

We then take them at their word, and accept what they tell us a true and form a belief around that testimony.  We could, of course, check the application on our phone showing us where the bus is in the case of the first example (that is if our local bus company provides such), or ask to see our friend’s cinema ticket in the case of the second example.  Person A or Person C could ask for evidence from Person B or Person D so that their claims can be substantiated.  However, it would no longer be testimony then.  There would evidence involved, and Person A or Person C would not have accepted them based solely on their word, and the beliefs formed by Person A or Person C would have been formed based on evidence. 

What follows will be a discussion of the former, rather than the latter.  This article will have a focus on the question of whether testimony can be justification for the formation of rational beliefs, looking at David Hume’s argument for testimony, as well as Thomas Reid’s argument, along with various examples and criticisms.

A friend’s testimony

A natural place to begin here would be with the above example of a friend telling us what they had done the previous night.  A friend or relative may tell us they went to the cinema to see some current blockbuster.  Or they may tell us of some experience they had when they went out to some restaurant, or pub.  Think about how many of these kinds of conversations we have had with our friends and relatives over the years. 

How many times do we ask for evidence that said friend or relative actually went to the cinema, or went to the pub or restaurant?  When they tell us of some encounter that they had at some pub do we demand to see evidence? Or do we remain sceptical of what they say until they can produce evidence for what they have told us?  Is it rational to simply form a belief based on the testimony of someone else? If one of our friends tells us that they were at the pub last night, or one of our friends tells us that they were at the cinema watching film X last night, are we rational to believe what they tell us?

Hume on Testimony

Consider what Hume argues when it comes to testimony.  Hume argues that there is a relational aspect between Agent A and Agent B when it comes to whether or not it is rational to form a belief based on the testimony of Agent B.  If we consider Agent B as the one telling the story of going to the pub the previous night to Agent A.  Consider too that Agent A has known Agent B for a very long time, and last night was Friday, and Agent A knows inductively that Agent B goes to the pub after work every Friday night to celebrate the end of another work week.  Consider also that Agent A has known Agent B for a very long time, and knows that Agent B is not in the habit of spinning tales, and generally tells the truth. 

Agent A also knows that Agent B has nothing to gain from telling him this.  In these circumstances would it not be rational for Agent A to form a belief that Agent B was at the pub the previous night?  Or the same if the Agent B’s testimony was about them going to the cinema?

According to Hume’s theory of testimony it would be acceptable for Agent A to form a belief that Agent B had been to the pub or the cinema the night before, and it also feels reasonably intuitive to say that Agent A’s belief would be a rational belief.  The history between Agent A and Agent B gives justification for the formation of Agent A’s belief about the activities of Agent B the previous night.  There is a level of trust through experience that has been built up over the years between the two agents. One that contributes to Agent A’s having a rational belief formation. 

Now, one might argue here that this history is no guarantee that Agent B is telling the truth.  After all, Agent B does not always tell the truth, so this could be one of those times that Agent B is not telling the truth.  There have also been occasions where Agent B has not been to the pub on a Friday because some something more important has come up, and Agent B had to attend to those matters instead.  Surely these would be rational defeaters for the idea that Agent A’s belief formation is rational?

Going To The Pub…

With regards to the latter, Agent B generally tells Agent A when Agent B has not been to the pub that Friday.  It needs to be remembered that there is a history of truthfulness between the two agents, something that a criticism such as this tends to forget.  That there have been occasions where Agent B did not go to the pub does not entail that Agent B did not tell Agent A that he did not go to the pub on these occasions. 

The aforementioned history of truthfulness means that this is not a rational defeater.  It is a reasonable criticism to bring up of course, but it is not criticism enough to be able to discredit the idea that Agent A’s belief formation based on the testimony of Agent B is a rational belief formation.  After all, there are reasonable justifications for rejecting the criticism that Agent B might not have gone to the pub the night before.

With regards to the former criticism, much the same can be said.  The criticism itself ignores the history of truthfulness between the two agents.  Yes, there are times in the past that Agent B has not told the truth, but what were these times that Agent B did not tell the truth?  What were the reasons that Agent B did not tell the truth on those occasions?  And what relation do they have to the testimony that Agent B gives about their exploits the night before? 

Is Being Sceptical a Rational Defeater in and of itself?

Do the untruths that Agent B uttered previously lend credence to the idea that Agent B might have acted out of character on this occasion being doubted?  Simply claiming that it is possible that Agent B may not be telling the truth does not seem to be a rational defeater for a history of truthfulness from Agent B towards Agent A.  It may give us reason to look at any evidence that could be presented to show that Agent B was not telling the truth on this occasion, but what it does not do is act as a defeater to the idea that Agent A’s belief formation is rational.  At least, not when the past history of truthfulness between Agent B and Agent A is taken into consideration. 

Instead, it could, and should, be argued that it is up to those claiming that this is the one time that Agent B might not be telling the truth to show that this is the one time that Agent B is not telling the truth. They are the one to show that the previous history is not a good indicator that Agent B is in fact telling the truth.  Agent C being sceptical of Agent B’s story is not the equivalent of showing that Agent A’s belief formation is irrational.

Claiming that it is rational for one friend to form a belief based on the testimony of another friend that has a history of honesty is all well and good of course, but what of cases where that history does not exist?  What about cases of a complete stranger?  Surely it cannot be rational to form a belief based solely on the testimony of a complete stranger?

Reid on Testimony

Here we have good cause to turn to Thomas Reid, and some of the arguments that he puts forward.  Reid argues that people are, in general, truthful.  People tell the truth most of the time, and value the idea of truth.  That is not to say that all people are truthful, nor is it to say that people are truthful all of the time.  We know from experience that those kinds of general statements are not accurate statements.  There are compulsive liars, there are people that lie when they have something to gain, there are people that lie in order to spare the feelings of others, among many other reasons.  Reid argues that God has created with a propensity towards truth.  However, an atheist will of course dismiss this idea.  However, this is not Reid’s entire argument.

Reid also argues that society itself would not function properly if the majority of its population leaned towards being untruthful.  If people were not honest most of the time, and people did not have a inclination towards truth, then we would not be able to pass on knowledge, we would not have formed bodies of knowledge, and we would never be able to truth what anyone was saying.  Instead, what we find ourselves is a fairly cohesive society, and what we find is that people tell the truth more often than not.  When we ask some stranger the time, in the majority of instances we find the stranger giving us the correct time. 

If we ask a stranger the directions to such and such a place, such as a local landmark or a local shop or public transport, we more often than not find that the stranger gives us truthful directions to where we asked.  Again, this is not to say that this always happens, there are always those out there that take pleasure in giving someone the incorrect time, or incorrect directions to such and such a place.  However, as is argued, we are more often than not met with a person that tells us the correct time, or gives us correct directions.

Experience Matters…

An individual’s experience when navigating society may be different than this of course.  They may have been brought up in an environment where people are more often than not untruthful.  In the case that someone’s experience with strangers is one that more often than not results in a situation where falsehood has been transmitted, then it would be irrational for them to accept the stranger at their word. Especially if still in the environment where people more often than not do not tell the truth.

However, when looked at in a wider scope, we find a different scenario to the person in this example.  At a wider scope we find the average stranger telling us the truth when we ask for directions, or ask for the time, or we ask if the bus has already been.  If our experiences match that of the wider scope, then we some justification for accepting the stranger based on their testimony, and we have some justification for claiming that our accepting the stranger’s testimony is rational, and the belief formed from that testimony is a rational belief.

Calling All Testimony Irrational

Consider the consequences of declaring that it is always irrational to form a belief based solely on the testimony of another person, especially that of a stranger.  Consider when we ask a stranger for directions to the local train station.  It seems unlikely that said stranger will be carrying physical evidence to back up that testimony.  People do not generally carry maps to the local area on them, at least not if they are from the local area, or have experience of the local area.  They use their experience of the local area to guide them around the local area, and they use their experience of the local area to give directions to those that might ask for them. 

If it is irrational to take a stranger at their word, and it is unlikely that the stranger we ask for directions will be carrying evidence to prove their claim that the directions to the train station are such and such, then is it not simply irrational to ask them for directions in the first place?  And if they do give us directions without giving us evidence to back those directions, and it is irrational to form a belief based on the testimony of a stranger, then is it not irrational to actually follow those directions? 

We must, in some sense, believe that what they are telling us is true before we follow those directions.  If we believe that what they told us is false, then following those directions is irrational because we think those directions are false to begin with.  If we think it is irrational to form beliefs without good evidence, and the testimony of a stranger is not good evidence, then we have behaved irrationally by following their directions.

Not All Testimony is Equal

It seems that there is a good case for accepting that there are times when belief formation based on the testimony of others, strangers and close relations alike, is rational.  Forming beliefs based on the testimony of others is commonplace, and the more one is to think about it the more one would realise just what a common occurrence it is in our lives.  As stated above though, this is not an argument that all testimony is equally valid, nor that all beliefs formed by testimony are rational.  It is simply an argument that to claim that it is never rational to form beliefs based on testimony is itself an irrational claim, and one that does not hold up. 

It may have been noticed that all of the above examples of acceptable testimony are simply mundane everyday examples, and mundane everyday claims.  That is the point though of them though, it is to show that there are acceptable forms of testimony, and that beliefs formed around those acceptable forms are rational beliefs.  There are justifications for accepting various forms of testimony, and justifications for forming rational beliefs based upon them.

Not All Testimony is Sufficient Warrant

However, as stated, this does not imply that all testimony justifies the idea that all beliefs formed from testimony are rational.  There are indeed times where it would be irrational to form a belief based solely on the testimony of someone else.  This includes the testimony of a close friend or relative who has a history and reputation for truthfulness.  For example, if a close friend or relative with a reputation for truthfulness tells us that they have just purchased a live 30-foot tall chimpanzee from eBay, then we have good justification for doubting and not accepting that testimony.  It is after all a claim that is far from mundane, normal, or every day. 

There are good reasons for us to doubt that testimony, and to ask for evidence to back up that testimony.  For example, chimpanzees are not normally 30-feet tall, nor does eBay allow the sale of chimpanzees in general.  It does not even entail that the close friend or relative is lying when they give us their testimony that they have bought said chimpanzee, they may indeed believe they have bought said chimpanzee.  After all, there are many con artists that exist on eBay.  It absolutely does entail that we are justified in rejecting their testimony, regardless of past history, though.

Matt Dillahunty’s Modern Day Debate Argument

As stated by Matt Dillahunty during a debate on Modern Day Debates between himself, Tom Jump, Randal Rauser, and Samuel Nesan titled ‘Sufficient Reasons to Believe in God’, ‘people can be mistaken, people can be wrong, and people can be biased’ when it comes to beliefs.  So, there are times where testimony simply is not sufficient to justify the formation of rational beliefs. 

Matt Dillahunty puts this forward as part of an argument against the validity of testimony being sufficient for the formation of beliefs.  As part of his argument Matt Dillahunty uses an example of someone telling him that a restaurant is six blocks away.  Matt Dillahunty states that he will take them at their word until he walks the six blocks and sees the restaurant there.  The proof comes when he arrives at the restaurant, and it is only at the arrival at the restaurant that he is rationally justified in believing that the restaurant is there, because as stated at the beginning of the paragraph ‘people can be mistaken, people can be wrong, and people can be biased’.

This argument seems to entail that we can never be rationally justified in believing something until we have seen the evidence that a particular claim is correct.  However, this would also mean that we are not justified even in taking them at their word until we arrive at the restaurant.  After all, we have seen no evidence that the restaurant is there, and they could be wrong, or mistaken, or biased. 

There are all manner of reasons for why they might not be telling us the truth, or why they might be mistaken; and if it the fact that someone could be wrong is sufficient for claiming that belief formation is irrational then it is irrational to even attempt to go to said restaurant.  Before embarking on our journey, we are obliged to do further investigation using maps before we are rationally justified in even heading towards the restaurant.  

Taking them at their word until we arrive at the restaurant is forming a belief that the restaurant is there, and forming a belief that they are not mistaken in their relaying of the information.  In other words, even embarking on a journey to see if the person was right is acting off of irrational beliefs according to this account. If we should not allow irrational beliefs to guide us, as is often argued, and we should only act on beliefs that are backed by proof, then we should never even embark on that journey to the restaurant unless we accept that we are irrational to do so.

What About…

Also, what of a situation in which we are speaking to a friend or relative who lives next door to the restaurant, or works there, or visits it every week?  Is their testimony still insufficient to use as the basis for the formation of a rational belief?  If the idea that someone might be wrong is sufficient to claim that their word cannot be the basis for the formation of a rational belief, and we must always be presented with proof in order for a belief to be rational, then we must discard much of what we believe to be rational beliefs. 

If we are only familiar with evolution through the works of others, and the experiences of others, and we have not performed all of the experiments ourselves, then we do not have sufficient warrant to call our acceptance of evolution rational.  We are, after all, simply going off of the testimony of others, we have not experienced these things first-hand; and if their ability to be mistaken is sufficient to discard their testimony as justification for belief formation, then any beliefs formed from their testimony are unjustified, unwarranted, and irrational.

We Could Justify the Testimony, therefore…

One could argue here that those works that we learned evolution from are written by people who have performed the experiments, and have spent a life time studying those things. We also have the ability to perform those experiments if we wanted to, and therefore have warrant to form a rational belief.  However, if the ability to be wrong, or mistaken, is sufficient to discard a testimony, then those scientists being human means that they have the ability to be wrong, and that is sufficient to discard their testimony.  Warrant only comes from us having performed the experiments ourselves, and seeing these things first-hand.  Until then, at least under this account, we have no warrant to form a belief about the accuracy of the theory of evolution.

This would also apply to something like knowing our name.  As we are growing older, we are called by our name by our friends and family, and we respond to that name.  We consider that to be our name, and would even claim that we know our name.  We would even consider that a child knows their name when they have the ability to recognise themselves as having that name, and responding to that name, and replying with their name when asked what it is.  It would feel somewhat ridiculous to say that the child only had an opinion that it was their name. 

Yet, on this account that Matt Dillahunty gives, that is exactly the case. At least until the child is provided with their birth certificate, and can understand that it is their birth certificate, and has read their birth certificate.  On this account provided by Matt Dillahunty, we do not have warrant to believe that our name is our name until provided with evidence that it is our name, evidence beyond the testimony of our parents.

There is Some Agreement With Dillahunty, but…

Of course, I do not wholly disagree with Matt Dillahunty.  The argument that Matt is making is that one must have sufficient evidence and justification before they can consider their belief warranted, and before they can consider their belief rational.  My criticisms of Matt’s argument may also even be taking it to an extreme that was not meant by him.  He could of course believe that the parent telling their child that their name is such and such is sufficient to warrant the child’s belief as rational.  He could simply be arguing that there is a certain level of justification needed for a belief, and that in certain circumstances that belief can be warranted by testimony alone.  

Which is the argument being made in this article.  That the testimony given as directions to the restaurant are sufficient to warrant a rational belief that there is a restaurant at location X.  Rather than getting to the location and discovering the restaurant being there as being the warrant for sufficient belief, getting to the location and discovering the restaurant does not exist would be a sufficient defeater for the belief.  We are justified in calling our belief rational based on the direction until we arrive at the restaurant and discover it is not there, not the other way around.


There are justifications for accepting testimony as warrant for calling a belief rational, and there are justifications that make that warrant stronger or weaker, such as the idea of expert testimony.  Those religious apologists who use testimony, or claim that the Bible is testimonial evidence, should not be so hasty here to claim some kind of victory though.  For there are reasons that act as defeaters for the sufficient warrant for rational belief when it comes to using testimony as evidence for the existence of God, or the authority and authenticity of the Bible. 

Defeaters such as conflicting testimony, reasons behind giving the testimony, that the Bible is not a direct documentation of events but rather the documentation of a chain of testimony, false beliefs by those giving the testimony, the many mistaken claims of miracles, and more.  There are good reasons for not simply accepting that testimony as sufficient warrant.  There are also good reasons for not accepting non-religious testimony, such as the eyewitness of a car crash.  Reasons such as the chaos involved in an event, how hard it would be to pay attention to the little details, and more.

However, none of that is a defeater for all testimony, and none of that is a good reason to deny that some testimony is sufficient warrant for rational belief.  If one was to stop and think about how often they have used testimony to acquire beliefs that they consider rational, and not only rational but correct, then most people would probably be shocked.  They would also be left in a position to discard a lot of their ‘rational beliefs’, or admit that there are times that testimony is sufficient to warrant a rational belief. 

The problem is not using testimony to justify a rational belief, the problem comes from not accepting defeaters to what one considers to be a warranted belief based on testimony, or even simply accepting defeaters to what one considers to be a rational belief, especially when it is a deeply held belief.

Some further reading and listening
More on Beliefs and Justifications
The Burden of Proof – Belief vs Claim – Court Room Analogy
Fresh AiR – S01:E06 – Reason and Rationality
Fresh AiR – S01:E05 – Belief, Truth, and Knowledge
SEP : Epistemological Problems of Testimony
IEP: Epistemology of Testimony