Then it is circumstantial. It cannot be empirical. As far as I am concerned
a piece of evidence that suggest something but do not actually prove it is by definition circumstantial evidence.
No, the two terms mean slightly different things.
Circumstantial evidence isn't directly connected to the conclusion. For example, if a husband takes out big a life insurance policy on his wife, then shortly after that she is murdered, we might infer that the husband committed the crime -- circumstantial evidence -- but the two events aren't directly related.
Empirical evidence is directly related to the conclusion, is scientific and measurable, but may not in and of itself be enough to support the conclusion. If a neighbor, peering through windows, says she saw the husband kill the wife, that is empirical evidence. If the wife's blood is on the husband's shirt, that is empirical evidence. But neither one in and of itself necessarily
proves the husband did it. The neighbor might be mistaken, the blood might have gotten there when the husband cradled his dying wife.
Most scientific experiments are designed to be empirical. If empirical evidence were the same as proof, it would make scientists' jobs a lot easier; they'd only have to do any given experiment once. Usually an experiment only gets them a little closer to the conclusion. Take things like global warming or evolution. There's tons of empirical evidence supporting both -- enough to leave little doubt in most scientists' minds of their existence -- but it is made up of lots of little empirical observations, none of which in and of themselves proves the conclusion. And some argue the evidence still falls short of proof.
In the case of Butch and Sundance, the circumstantial evidence might be that they slept in the same tent. Empirical evidence could be somebody watching them through binoculars.
Here are some definitions from the web:
circumstantial evidencen. Evidence not bearing directly on the fact in dispute but on various attendant circumstances from which the judge or jury might infer the occurrence of the fact in dispute. For example, from the evidence that a person was seen running away from the scene of a crime, a judge or jury may infer that the person committed the crime.
em·pir·i·cal (m-pîr-kl)adj.
1.a. Relying on or derived from observation or experiment: empirical results that supported the hypothesis.
b. Verifiable or provable by means of observation or experiment: empirical laws.
2. Guided by practical experience and not theory, especially in medicine.
