Monday, January 04, 2016

Belief without Evidence is Crucial for Knowledge

Being a reasonable person is a great goal; no one wants to be thought of as foolish or gullible. But does being reasonable mean one needs to have reasons for all of one's beliefs? I've run onto many people who would answer "Yes" to that question. I mean, even the word "reasonable" contains the root of "reason!" How could one be reasonable without having reasons for one's beliefs?

This kind of thinking is prevalent in the online conversations I have with atheists. I recently offers one in this example. But not only is my interlocutor unreasonable in asking for evidence for what would be rather benign claims (like a person's academic achievements in casual conversation), he is wrong about what constitutes reasonable belief at all.

Principle of Credulity

In the introduction of his book The Evolution of the Soul, Philosopher Richard Swinburne lays out some key principles we all use in our reasoning. The first is the Principle of Credulity. Swinburne defines it as "in the absence of counter-evidence probably things are as they seem to be."1 This principle holds that we should basically trust what our senses tell us. While sometimes our sense can be wrong, we trust them to tell us true things about the world, for that's simply how we observe the world. As Swinburne points out:
Without this principle, there can be no knowledge at all. If you cannot suppose thigs are as they seem to be unless further evidence is brought forward—e.g. that in the past in certain respects things were as they seemed to be, the question will arise as to why you should suppose the latter evidence to be reliable. If ‘it seems to be' is good enough evidence in the latter case, it ought to be good reason to start with. And if ‘it seems to be' is not good enough reason in the latter case, we are embarked on an infinite regress and no claim to believe anything with justification will be correct.2
This is the key point in when debating with a person who will only accept something based on evidence or that evidence only counts if it is scientifically testable.

What Counts as Evidence?

Take a claim like the one Paul made in 1 Cor. 15:5-7 that the resurrected Jesus appeared to Peter, then all of the apostles, then to James, and then to five hundred people, and lastly to Paul himself. Paul is offering evidence in the form of eyewitness testimony, both his own and of others. If one discounts that as evidence, by what criteria are they doing so? If it is because eyewitnesses can get things wrong, then why ever allow them in courts? What about scientist who base all of their research on visual observation of events or instruments. Doesn't it follow that their eyes could deceive them as well?

The objector might claim, "My problem with that testimony is we simply don't observe people rising from the dead!" But that objection really begs the question, as Swinburne notes. If observation cannot be trusted, why should we trust the observation that people don't rise from the dead?  Maybe they have in the past and we missed it!

If you press for evidence before you believe anything, you will never reach a starting point. There is always the question of "What is the evidence that backs up the evidence you're presenting? Why should I believe that to be true?" It becomes as Swinburne said an infinite regress, where one can never justify anything at all.

In the next post, I highlight another of these principles, one that states why in the absence of any evidence to the contrary testimony specifically should be believed. Stay tuned.


1. Swinburne, Richard. The Evolution of the Soul. Oxford: Clarendon, 1986. Print. 11.
2. Swinburne, 1986. 12.
Image courtesy jon crel and licensed via the Cretive Commons Attribution 2.0 Generic (CC BY 2.0) License


  1. Great article Lenny good stuff I have thought about this as well that a sceptic can have an endless regress of being sceptical of literally everything you present without once being sceptical of their own scepticism or evidence.

  2. [It's been a few days and I haven't seen my comments posted. Just wondering if I didn't actually hit the "Publish" button or something else. So here they are again. -- FoK]

    I must say that I'm truly baffled by this article.

    1) Regarding eyewitness testimony, you write "If [one discounts eyewitnesses] because eyewitnesses can get things wrong, then why ever allow them in courts?" Because people do, in fact, witness crimes and can attest to various facts. But if you've ever been on a jury that listened to eyewitness testimony, you've probably also received instructions from the judge that as a juror you are free to discount the testimony of any witness you deem to be not credible.

    Have you never seen the documentary "The Thin Blue Line"? Or the movie "Twelve Angry Men"? Or any of a hundred films (fictional and not) about black men on trial in the segregated south? Are you not aware of the Innocence Project and the number of people who were convicted on eyewitness testimony and are now being exonerated by DNA evidence and other hard science?

    Eyewitness testimony is the least reliable of any evidence presented in court.

    2) You must know there are videos on the internet claiming to show people being raised from the dead, yes? Why are you concerned with justifying the credibility of 2000-year old "eyewitness" testimony of resurrection when you have these videos? Do you not believe the videos? Wouldn't they lend credence to Biblical claims of resurrections, if true? Why not point to them? Do you not find them credible? If not, why not? Wouldn't the fact that a resurrection is on film be stronger evidence for a past resurrection than ancient eyewitness testimony? And if you don't believe these videos, why should you believe the less trustworthy "eyewitness" testimony of two millennia ago?

    3) You write "If you press for evidence before you believe anything, you will never reach a starting point." Bull.

    If someone says to me "You know, electrons behave like particles AND waves." I don't have to believe it prior to being presented with the double-slit experiment. And yet when the experiment is performed, and performed again, and again, and again, then I can believe it. And what was my starting point? A test built on prior knowledge and a hypothesis about what would happen if electrons possess such duality. Not the say-so of any person.

    Yes, it is dependent on believing certain other things. But all these things are again testable. And there is no infinite regress. It stops with our reliance on the trustworthiness of our senses which is reinforced by continuous experience.

    Here's the key: this is (based on your brief summary of Swinburne) exactly what the Principle of Credulity seems to be stating, that our SENSES are reliable. That is, we can believe that what is presented to them is what is presented to them. We can believe that what we hear is what is being said, that what we read is what is actually on the page.

    But that's as far as it goes. It does NOT require that we believe the content of anything we hear, only that we actually hear it. We need not believe that what is written is relating literal truth, only that the words are actually on the page. Believing the content is a completely different level. And you need to make that distinction.