The Nature of Evidence

Evidence is crucial to our attainment of knowledge. David Hume, Bertrand Russell, A.J.Ayer, have all called for the necessity of having evidence for a thing, in order to believe it. But there is little guidance as to the nature of evidence, or determining its validity, possibly because philosophers such as these had purely materialistic expectations.

So what are the elements of evidence? How do they relate to our experiences? And how can we know which evidence is valid, and which is not? We must have a firm grasp of these things in order to sort through the onslaught of output from the media as well as the sciences, not to mention the necessity of forming a valid and rational wordview.

Types of Evidence: Physical and Non-Physical.
Many times evidence is thought to be only material, as in a piece of physical matter, or possibly the behavior of physical matter under certain conditions. This is empirical information, which is created experimentally, and repeated for confirmation. The findings must be falsifiable, in order to preclude tautological, or definitional statements that are not evidence. But this is not the only type of evidence.

Evidence can also be historical, as with forensic material or information which is found and then interpreted. This type of evidence must be scrutinized for plausibility of the interpretations, which are of necessity extrapolated beyond the actual found data.

In legal situations, the concept of evidence includes, along with empirical and forensic evidence, non-physical information, as is the case with witness testimony and informational evidence such as email or other documents.

Limits of Evidence: What can we be certain that we know?
It seems likely that most philosophers agree at least this far: we can possibly know that which is introduced to us through our senses; and we can possibly know that which is created internally in our minds. And here the agreement stops, as theories of knowledge burgeon on the bookshelves. Maybe our senses lie to us. And maybe our internal thoughts are fantasies, dreams or hallucinations. If so, we are left without any possible firm understanding, or knowledge of either external reality or internal reality. This position goes back in history as far as Pyrro, and is sometimes called Pyrronism, or in modern terms, Logical Positivism.

But practically speaking, do our senses really lie to us? If so, how often? And how badly off from reality is the lie?

And do our internal thoughts consist only of fantasies, dreams, hallucinations or even biases and prejudice? How often do these consume our internal thoughts with errors, and how often are we actually able to be rational?

So the question resolves to one of probabilities. Can we know the probability of the rationality of our particular thought process? Can we know the accuracy of our senses in reporting the external world to us?


All evidence is probabilistic.
David Hume, the famous empiricist, insisted that cause and effect could not be guaranteed, because we only observe the effect in a “constant conjunction” with the cause, and this is not enough to absolutely guarantee that the next cause will produce the same effect. If this is true, then no empirical findings can be called absolute. However, if a substantial number of replications of the findings always shows the same results, then the findings have a high probability of accuracy. The necessity of using probability in describing empirical findings was also argued by Popper and Stove.

Evidence is the meaning given to data.
In court, evidence is presented in the form of material items, testimony, documents etc, which are all considered just data unless proven “relevant”, ie., having meaning and pertinence.

“Relevance”, “meaning” and “pertinence” are not material items, having no physical characteristics such as size, and mass or energy content. From a material standpoint then, these concepts are outside or beyond the realm of the physical. In other words, they are metaphysical. Thus the demand for physical evidence without any metaphysical content has no possible resolution. As with all “ideas” and “concepts”, any meaning bestowed upon physical instances is metaphysical.

Role of Materialism in Evidence.
Materialism has two aspects: voluntary, or functional, materialism; and philosophical materialism. Empiricism is a process of understanding natural occurrences. In order to satisfy a need for measurement in the quest to understand physical occurrences, empiricism has voluntarily placed upon itself the “functional materialism” position. This means that only physically manifested instances are considered for testing, using the “scientific methodology” of the empirical procedure.

Philosophical Materialism, on the other hand, insists that there is no existence outside or beyond the physical boundaries. (Being a philosophical idea itself, and therefore non-physical, the philosophy self-refutes). This is not a valid limitation to the boundaries of evidence.

Probabilities
If the entities of “meaning”, “pertinence”, and “idea” are thought to exist, then the existence of metaphysical entities is also assumed. But how is one to determine the probability of any given metaphysical concept being valid?

Many metaphysical entities can be experienced as a group. For example, if a witness testifies to his experience of an event, all who hear the witness are able to share in the information. Perhaps not all who hear the testimony will agree as to its validity. Nonetheless, the testimony is non-physical, and those who hear it share the information. A transfer of a metaphysical entity to a group has occurred.

How can we decide whether non-physical evidence is valid? This can only happen in the same fashion that material evidence is determined valid and not fraudulent. A process of discernment must be applied to the evidence and a judgment must be reached concerning the relative plausibility. This true of all evidence, and non-physical evidence is no different. While discernment is discussed elsewhere, it too is a non-physical – metaphysical – entity.

Discernment of the validity of evidence can only succeed under rigorous and persistent intellectual integrity, which means using only the evidence to make the determination, not personal bias.

Some possible biases:

Materialist-Atheists will declare that only evidence that is physical can be believed.

Other Atheists declare that while there is no deity, atheism does not preclude any other non-material existence.

Agnostics declare that without firm evidence (material), no decision can be made. This is essentially the same as Materialist-Atheist.

Empiricists have no claim on non-material evidence, except that it is not physically testable in order to be verified.

Forencists also have no claim on non-material evidence except that it is not physically locatable in order to be “found”.

Common sense, the process. Common sense is not a bias in the sense that it is a process. Because that which is traditionally called “common sense” varies outside the realm of Philosophical Materialism for most Americans, is it any wonder that the proponents of Philosophical Materialism claim that there is no such thing as common sense? Declaring it nonexistent does not make it so. And carefully examining the criteria for non-physical entities that so obviously do exist, one can only conclude that the restriction to Philosophical Materialism is both irrational and a false constraint upon evidence.

Common sense, the prejudice. Along with those things that we learn empirically as we mature – fire being hot, for example – we are prone to acquiring non-rational biases from our mentors and culture. Prejudice is a belief that is held despite its non-rational character. In this sense, some “common sense” is a bias against the rational, thereby prejudicing the discernment process.

Prejudice.
Prejudice can only be fought through persistent intellectual integrity.

Richard P. Feynman, Nobel Laureate in Physics, had this to say concerning intellectual integrity:

“It’s a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty – a kind of leaning over backwards. For example, if you’re doing an experiment, you should report everything that you think might make it invalid – not only what you think is right about it: other causes that could explain your results; and things you thought of that you’ve eliminated by some other experiment, and how they worked - to make sure the other fellow can tell they have been eliminated.
Details that could throw doubt on your interpretation must be given, if you know them. You must do the best you can – if you know anything at all wrong, or possibly wrong – to explain it. If you make a theory, for example, and advertise it or put it out, then you must also put down all the facts that disagree with it.”

And,

“The first principle is not to fool yourself- and you are the easiest person to fool. So you have to be very careful about that. After you’ve not fooled yourself, it’s easy not to fool other scientists. You just have to be honest in a conventional way after that.”

Finally,

“I’m talking about a specific, extra type of integrity that is not lying, but bending over backwards to show how you’re maybe wrong, that you ought to have when acting as a scientist, certainly to other scientists, and I think to laymen.”

Richard P. Feynman, “Surely You’re Joking Mr Feynman!”, Bantam, 1985, pages 311- 313.