There are reputed to be at least 99 of them.
In glacial geomorphology, when we are trying to interpret the impact of glaciation on the UK landscape, we are dealing with "circumstantial evidence". However, interpretation is informed by direct knowledge of what glaciers do and how they work, in the field, in places like Greenland and Iceland. I have been to both those places, and have observed glaciers at close hand -- I hope it can therefore be assumed that I know what I am talking about when I form opinions about what has happened in the UK. If I am right, my evidence will be accepted by my peers. If I am wrong, one of my peers will come along and falsify my hypothesis through the provision of more reliable circumstantial evidence, well founded in field observations elsewhere, where processes are observable and measurable.
So when I look at large glacial erratics in a landscape which has been repeatedly affected by glacial processes, and call them glacial erratics because that is what my accumulated experience tells me, I will accept a challenge from another glacial geomorphologist who thinks he or she has better evidence than mine. But I will not accept a challenge from an archaeologist who knows nothing of glacial geomorphology and who simply says "I do not accept your evidence." Such a challenge is intellectually dishonest; it fails to accord me the respect that I deserve as a specialist in this field; and it is a waste of everybody's time.
By the same token, I am not an archaeologist, and if I wish to say something contentious or to challenge a well-founded hypothesis based on sound direct or indirect evidence, the burden of proof rests upon me to come up with something better, and to marshall my evidence in support of what I am saying.
Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either (a) presumed to be true, or (b) were themselves proven via evidence, to demonstrate an assertion's truth. Evidence is the currency by which one fulfills the burden of proof.
Many issues surround evidence, making it the subject of much discussion and disagreement. In addition to its subtlety, evidence plays an important role in many academic disciplines, including science and law, adding to the discourse surrounding it.
An important distinction in the field of evidence is that between circumstantial evidence and direct evidence, or evidence that suggests truth as opposed to evidence that directly proves truth. Many have seen this line to be less-than-clear and significant arguments have arisen over the difference.
Circumstantial evidence directly supports the truth of evidence, from which the truth of the assertion may be inferred.
Evidence in science
Main article: Scientific evidence
In scientific research evidence is accumulated through observations of phenomena that occur in the natural world, or which are created as experiments in a laboratory or other controlled conditions. Scientific evidence usually goes towards supporting or rejecting a hypothesis.
One must always remember that the burden of proof is on the person making a contentious claim. Within science, this translates to the burden resting on presenters of a paper, in which the presenters argue for their specific findings. This paper is placed before a panel of judges where the presenter must defend the thesis against all challenges.
When evidence is contradictory to predicted expectations, the evidence and the ways of making it are often closely scrutinized (see experimenter's regress) and only at the end of this process is the hypothesis rejected: this can be referred to as 'refutation of the hypothesis'. The rules for evidence used by science are collected systematically in an attempt to avoid the bias inherent to anecdotal evidence.
Burden of proof
Main articles: Legal burden of proof and Philosophic burden of proof
The burden of proof is the burden of providing sufficient evidence to shift a conclusion from an oppositional opinion. Whoever does not carry the burden of proof carries the benefit of assumption. Whoever bears the burden of proof must present sufficient evidence to move the conclusion to their own position. The burden of proof must be fulfilled both by establishing positive evidence and negating oppositional evidence.
There are two primary burden-of-proof considerations:
• The question of on whom the burden rests.
• The question of the degree of certitude the proof must support. This depends on both the quantity and quality of evidence and the nature of the point under contention. Some common degrees of certitude include the most probable event, reasonable doubt, and beyond the shadow of a doubt.
Conclusions (from evidence) may be subject to criticism from a perceived failure to fulfill the burden of proof.
The Burden of Proof