What is evidence anyway?

     Evidence is the term applied to the information indicating whether a claim (synonym for a belief, hypothesis, statement, or argument) is True or not.

Because we are imperfect systems (we are fallible), the information provided to support a claim of Truth must satisfy each of the following three ideas.

1) the information must be observable (measurable).

-we must be able to measure the claim in some way. 

If the evidence to support your claim is not observable, then it becomes impossible to detect. If we cannot detect it whatsoever, then we cannot logically include this as evidence toward your claim. 

2) the information must be repeatable.

-we must be able to repeat the findings through experimentation. Findings that are not repeatable through subsequent testing cannot be used as evidence. This is another word for a miracle. Most faith-based religions we have recognize miracles as a source for our justification in a god-belief. Because our senses are faulty, we cannot use a single incident as evidence of anything. Is there a greater chance that the laws of space and time were bent for us personally, or that our blood sugar may have been a bit low? We require repetition to eliminate known errors of our senses and our bias. 

3) the information must be falsifiable (testable). 

-we cannot use circular logic to support our claim. It is not logical to say something is True because it is True. Likewise, it is not logical to say something is True because it cannot be proven false (outside of pure deduction). To be falsifiable is synonymous with our claim being testable. Logically, these two words have nearly identical meaning. Something which cannot be proven false is synonymous with it not being testable in the first place.  Therefore, if the evidence cannot be demonstrated to be possibly be wrong then we logically cannot use towards the validity of a claim. 

     Because we could always be mistaken (and are innately biased), the scientific process as a whole requires a level of peer-review to further process any evidence provided toward a claim of Truth.