Objective Reality or how can we know something?
The three states are True, False or (don't know/don't care). It appears to be human nature to live with only two states, the true or false. People make the error of making the don't know/don't care state either true of false. The legal system has had to deal with the problem of what we can know and has developed the law of evidence (Qld Evidence Act 1977).
Summary of the law of evidence.
Initially disputes were solved by "trial by battle", defeat was clear proof of guilt. The next development - trial by inquisition of those on the spot, required no rules. Those making the accusation acted as judge, jury and witnesses, and conducted such inquiries as they deemed necessary without regard to any procedures.
Guilt would be determined by local knowledge, hearsay, reputation and prejudice rather than the facts of the case.Only witnesses can give evidence in a court and their statements are evidence only when sworn or attested to. Corrupt Police can let the guilty go free stating "insufficient evidence" because they did not take any sworn statements. Evidence is what the witness saw and heard at the time of the incident when it is sworn or attested to. Evidence that is relevant will change the probability of the existence of a fact in issue in a trial. Some hearsay can be evidence such as confessions. The hearsay evidence must have been made by a person with reliable personal knowledge of the facts. This means they saw and/or heard the incident and told someone about what they saw and heard.
An Example.
My mother told me that Faye gave her son, Glenn Johnson $400,000.00. When I asked how do you know this my mother said "Faye told me". "But Faye lies and you can't believe anything she says." I said. All you can say is that Faye said she gave Glenn $400,000.00. Believing that Faye gave Glenn $400,000.00 is a mistake and most probably wrong.
How do people develop their world view - their understandings of the world?
The Longest line experiment tells us that over 60% of people take their view of reality from others and do not look for themselves. They believe what others tell them. The Longest line experiment. People who invent nasty stories about others and go and tell those stories can have a very big impact. The power to influence of the Third Person is very large. When those stories affect people emotionally they are even more influential. Read up on the Techniques of influence.
I can remember reading a spoof article about how governments want fluorine in the water because it kills of a part of the brain that makes people individuals and this makes them easier to control. References were made to professors and doctors through out the article. The fear that the article invoked in some people was so large that they were unable to not believe what was being said. Invoke a strong emotion and what is said is more likely to be believed.
How can we know?
By knowing how things work we can know what is plausible. This does not mean that it actually happened, it means we can reject everything that is not plausible.
Various types of decision making and diagnostic procedures from real world where things either work or don't work - fixing computers. GPs where there is guess and test or try approach. Alternative medicines such as aroma therapy, rake and Psychiatry where there is no cause and effect but rather a categorizing based on an opinion approach. Where even the theory is un-testable and therefore probable wrong. Then there is the three categories of knowledge - what we know, what we know we don't know and the biggest - what we don't know we don't know.