Evidence: What is it?

Let’s ask ourselves some questions about evidence: What’s it for? What qualities would we like it to have? What counts as evidence? What doesn’t count as evidence?


Whether we are on trial for some criminal offence or trying to discover the answer to an important scientific or social question, we need to be able to recognize evidence. How would we like it to perform? Would it be any good if it were questionable? A matter of opinion? If it was dubious? I think not.


Ideally, to be effective, evidence must be beyond question, beyond doubt. It should be like playing an ace, a killer blow, a cold hard fact. Anything less than that would not be foundational; it would require personal belief, would be just an individually chosen attitude towards a proposition, worthless. There is little point presenting an item of supporting information and having it disputed; that would achieve nothing. So what might deliver the required standard for evidence?


How about testimony or witnessing? Testimony is a witness account sworn under oath; I’m not sure how, in these educated times, putting a hand on a Bible is supposed to help a person remember an event more accurately or make them more truthful. Why a Bible, anyway, why not a Quran or the Book of Mormon?


There are two types of witnesses: eye witnesses and hearsay witnesses. Those are really good names: eye witnesses saw an event with their eyes – they were actually present, hearsay witnesses heard about it with their ears; somebody told them about it; they got a secondhand, third-hand or more remote account of an event that they DIDN’T attend. They may even be retelling something that happened long before they were born, something they were taught to parrot as infants! (Incidentally, that is the nature of the written accounts in the gospels.)


Hearsay is what makes up our ‘Oral Tradition’ and we all know how stories get ‘improved’ in the retelling by the desire to please an audience; this tendency has even given rise to common expressions such as ‘Chinese Whispers’ and ‘Fisherman’s Tales’. Hearsay witnesses are considered to be so unreliable they are not accepted in court, but eye-witnesses are not much better: in an experiment to test the effectiveness of identification parades, 48 out of 56 people, who saw the ‘crime’ enacted, picked out the wrong person! In fact, we now know that one in fifty of us is ‘face-blind’. Perhaps this explains why the Royal Society, the world’s first scientific club, founded in 1661, adopted the motto, Nullius in Verba (‘nothing in words’ or ‘take nobody’s word for it’).


How about experience, is that evidence? Well, reported experiences immediately fall foul of the problems of witnessing – can you believe the reporter’s account? How would you know whether the reporter was describing a dream or an epileptic or psychotic incident, or a ‘revelation’ or an ‘epiphany’?


So what about personal experience? It’s simply unshareable – I can’t experience your grief and you can’t experience my orgasm, which is probably just as well! I personally experience ‘visions’, which I know are actually the migraine aura, but it makes me realize that I can’t even trust my own sensory experience, let alone yours.


Even shared experiences can be distorted – audiences can be deceived by conjurors, congregations can be swayed by powerful orators, drugs can be involved at festivals, it can be difficult to see what actually happens during an event where police try to control a crowd, etc. I know a theistic presuppositionalist will say, “Everything is an experience, including the observations made by a scientist.” A few hundred years ago I would have agreed with them. Poor quality telescopes enabled Italian astronomer Giovanni Schiaparelli to think he saw ‘canals’ on Mars in 1877 and early microscopists thought they saw little men, ‘homunculi’ in sperms! But things are very different now. Today, instruments make most observations and computers statistically evaluate their digital output; no humans are involved. Sometimes the instruments are in places where men cannot go, such as inside a nuclear reactor or on the comet being orbited by the Rosetta spacecraft. Besides which, a theist criticising their opponent’s position is not the same as them providing evidence for the existence of their ‘god’.


What about intuition? Can’t we just intuit that a proposition must be correct? Sadly, no, some things are simply counter-intuitive. Intuition led men to believe that a heavy rock would fall faster than a light one of identical dimensions. Wrong! Until a hundred years ago, it seemed intuitive that time proceeded at a steady rate. Untrue! The passage of time is relative to the speed of the observer. There is no reliable connection between mental concepts and reality. Why should thoughts be true? That’s why we must do testing for a match with reality.


How about books? Are books trustworthy referential sources? Some books are not even intended by the author to be taken as true, but what about books that are a mixture of fact and fiction? Few would claim that all text should automatically be taken as ‘gospel truth’. So how do we tell which books are reliable sources of information and which aren’t? Take a telephone directory; we can check that it’s correct by making a few calls. What about a school science book? Just repeat the experiments described in it to find out whether it’s reporting the truth. Those books are testable and, if they pass the tests, can be regarded as reliable references. It’s testing that makes the difference. To focus on the Bible, several passages actually defy the Laws of Physics, Christians excuse this with the untestable claim that they are ‘miracles’. Defending a claim with another claim is known as an ad hoc fallacy. Couldn’t I stand up for the existence of fairies by claiming that they are miraculous? How would you refute me? Even most theologists agree that ancient religious texts are not intended to be accurate accounts of history; they are religious propaganda.


What about argument then, is that evidence? Well, considering you can pay a lawyer to argue for or against whatever case you like, I think not! An argument is just a mental construct, a concept, which may be right or wrong. You can have an opinion about an argument. We can CHOOSE whether to support it or not. Some theists support the ontological argument for god, others don’t. Some theists back their faith with Aquinus’ First Way, others don’t.


Evidence isn’t like that; it’s not optional! Ok, philosophy attempts to make thinking rigorous, but even apparently logical syllogisms cannot be guaranteed to be correct. Many so-called ‘deductions’ have turned out to be flawed and even those that sound convincing are just intracranial concepts until verified or denied by evidence from external independent objective sources. Otherwise, how would we know whether an argument is a duff concept like an idea for a Perpetual Motion machine or not?


Keen amateur philosophers, locked into their faith in the infallibility of argument, coupled with their lack of understanding of science, often imagine that an argument proves something and, to be refuted, it needs a counter-argument. Nothing could be further from the truth; an argument is not the end of discovery. It’s merely the end of conceptualizing, which is the beginning of investigating for a match with reality. They can argue and counter-argue to their heart’s content, what is actually needed is to say to the universe, “Here’s my concept, it sounds logical to me, is it an accurate model?” And then we must start looking out for observations. Testing with logic beats guessing with logic. Philosophy is like urine: it’s ok to drink it when there’s nothing else, but an external source of water will always beat it.


So, how do we get the unquestionable objective standard we need evidence to have? It’s taken a while, but scientists have developed a method for obtaining evidence. It involves making observations and repeating them. Ideally, if anyone, anywhere, and at any time can repeat the investigation, given access to the appropriate equipment, and get the same result, then we have got evidence. Cold hard fact. Killer information.


It’s evidence that turns hypotheses (untested assumptions that may or may not be well argued), such as ‘there is a god’ or ‘there are fairies’ into conclusions. We need it. Look what it’s enabled us to do…