One definition of knowledge is true belief based on strong evidence. What makes evidence "strong" enough and how can this limit be established?


be knowledge, as there is no testable evidence? Is it not a purely scientific view to say that all evidence must be testable by scientific means? Many religious people believe there is evidence of the existence of higher beings in events that are considered “miraculous”, such as the sudden healing of an ill person thought to be beyond hope, which medical science cannot explain. Others would argue however that there are many natural phenomena which modern science cannot explain but we have evidence of, such as spontaneous human combustion – the process by which people catch fire without source of ignition, and burn at temperatures high enough to burn bones, but do not damage their surroundings. Therefore though current technology may not be able to pinpoint the reason why miracles happen, future knowledge may be able to. Indeed, some people have proved the resurrection of Jesus through the principles of law – the six disciples who were witness to his resurrection all testified to it, without any reason to lie.   Maths is what many would call absolute knowledge, in that it cannot be disproved once proved. However, this is because maths is an abstract concept – 2+2 equals 4 because this is one of the basic premises upon all of which math is based, you cannot therefore disprove it. Mathematical paradigms are established through proofs, which are a series of logical arguments. While evidence can be used to show existence of paradigms, it cannot prove them – they must be shown as true using already established rules and deductive logic (the process of taking already established ideas and building upon them). In the case of Fermat’s last theorem, numerical evidence was given to show it was probably true, as even with computer aid, no numbers could be found to disprove the theory. This however did not constitute a proof, and it took over 300 years from the invention of the theory to its final proof. Therefore in mathematics, knowledge is not based on evidence, it is based on proof. This does not mean we cannot look at strength of evidence in mathematics. Evidence is used to show theories which might be true, and in this case, strength of evidence is purely based on amount – the more examples you can give where the theory works, the stronger the evidence.  Science is in essence a series of ideas and disproof’s – one has an idea, one shows it fits certain patterns, and that idea holds true until it is disproved. It is therefore unlike mathematics in that proven theories can later be disproved. It is also important to note that theories may be used which are known to be incorrect, but work for many examples. This is due to a lack of a better theory to explain behaviour. For example, the model of the atom with its orbiting electron’s cannot work, as a moving charge would produce a magnetic field, taking away the electrons energy and eventually stopping it. This does not happen, however we stick to this model as evidence shows it works with most cases. Of course it is realistic to believe eventually someone will create a theory that better models observed behaviour, and finally disprove the current one. This is the process of induction - the creation of theories, their testing, and eventually their falsification. Strong evidence in physics is therefore evidence that shows a pattern across a wide range of examples. Strength is therefore defined by regularity of the evidence – the more consistent results are, the stronger the evidence for the pattern. The amount of evidence is also important – the more evidence you provide, the wider the range of the theory, although this does also include the recording of conditions, such as room temperature, humidity, pressure etc.   The origin of the evidence, as it takes into account authority – if, in a university laboratory, a pattern is shown by a PhD scientist, the results will often be more credible than those produced in a school laboratory by a 15 year old student. Even if the student shows a pattern not yet noticed, the experiment will often be repeated by PhD scientists to show it is correct. This however implies the problems with authority, in which authority does not always imply correctness – well established scientists have been known to edit (“fix”) results so as to prove their theory. Take for example Einstein’s work on the nature of the universe – he looked at speeds at which stars moved and calculated that the universe was in a constant state of expansion. However, this did not fit with his beliefs, so he then introduced the “cosmological constant” to his calculations to show a static universe, even though it was later shown that the universe was expanding. Einstein purposely changed his formulae to allow for what he believed happened.  History is the study of evidence from which we gain an understanding of past experiences. There is a wide range of types of evidence, some stronger than others. A written source, for example, could be considered less reliable as it involves the perception of the author (which can be incorrect) and could be biased due to the author’s emotions, though the individuality and subjectivity of the source could be valuable (for example eye-witness accounts). Pictorial evidence, photos and videos, provide strong evidence (if not edited), though they may be partial or falsified. We therefore see that evidence strength is based on bias - the less biased the source, the stronger the evidence. Amount of evidence is important here too, as if many sources corroborate together, the evidence they produce is stronger than that of a lone source. The biggest problem historians face is obtaining enough evidence – the greater the age of the event they are studying, the less evidence they will find, as evidence is destroyed (intentionally or unintentionally). For example, the Bayer tapestry is the only evidence we have of the Battle of Hastings, however it is a secondary source (its producer was not at the battle) and it was created long after the actual battle. As a result, we believe this to be the course of the battle, for even if it was not, we have no other evidence to provide other narratives. There is also the problem of access to evidence. There is a great amount of evidence on the events of the Cold War, however half is stored in Russia, and has only been accessible for just over 10 years. Before the release of Russian information, we had only the American evidence on the events of the war. Historians therefore became biased as they only had half the evidence to work from. Therefore evidence in history is strongest if there is a lot of it, it all corroborates, and it comes from more than one source.  In conclusion, there is only one universal measure of evidence – that is that evidence is strongest if it makes everyone confirm or change their beliefs. Beyond that, rating strength of evidence is applicable only to individual areas of knowledge. The only consistent measure seems to be amount – in every case looked at here, we have seen that the more evidence provided, the stronger the evidence is. In religion many would say the evidence is through the existence of believers, and the accepted religions are often the ones with the most members – Christianity is more credible than Jedi-ism for example. Though in maths we have seen that we can prove completely a theory, when we have no proof, evidence is a good indicator that a theory exists. In science there is no way of proving anything, therefore our only indicator comes through large amounts of evidence. History is similar, where we can never prove something happened unless we witnessed it ourselves; however large amounts of evidence are a good indicator of the existence of an event.