Then what does evidence support? What is the point of getting evidence?
Is evidence irrelevant in support of a case against a criminal?
The point of evidence is that when you have two theories, one of which predicts A, while the other predicts B, then a proper test can eliminate one or the other of the theories from consideration. It does not, however, indicate that the theory that has been corroborated is correct.
In the case of a criminal cases, there are two types of evidence that are used. They are classified as direct evidence and circumstantial evidence. If, for example, a man witnessed a murder and picked the murderer out of a line-up, then that is
direct evidence and is conclusive on its own.
On the other hand, there is
circumstantial evidence. One example might be fingerprints on the toilet handle in a murdered victim's house that are believed to match the fingerprints of a suspect. As I have already pointed out, fingerprint evidence is usually quite unreliable, but for the sake of argument let's say that fingerprint evidence could be elevated to a science and the expert was able to say that the print matched the suspect's print in 17 points
and that there are only, statistically speaking, 2 other people in a city the size of Los Angeles who would have a 17-point match with the fingerprint in question.
Even so this information is not conclusive in itself. If the suspect denied going into the victim's house at any point in the past, that would raise the suspicion that the suspect is lying and therefore has something to hide. If, however, the suspect merely remained silent and let his lawyer do the talking, then the print would not be enough evidence to determine that the person was guilty of the crime. There are many possible explanations for prints on a toilet handle in someone's house.