16e FEDERAL REPOfiTEB. �you an exact definition of the terms, for I do net know of any suc- cessful attempt to do so. �As to questions relating to human affaira, a knowledge of which is derived from testimony, it is impossible to have the same kind of cer- tainty which is created by scientific demonstration. The only cer- tainty you can have is a moral certainty, which depends upon the confidence you have in the integrity of witnesses, and their capacity to know the truth. �If, for example, facts not improbable are attested by numerous wit- nesses who are credible, consistent, and uncontradicted, and who had every opportunity of knowing the truth, a reasonable or moral , cer- tainty would be inspired by their testimony. In such case, a doubt would be unreasonable, or imaginary, or speculative, which the books say it ought not to be. And it is not a doubt whether the party may not possibly be innocent in the face of strong proof of his guilt, but a sincere doubt whether he has been proved guilty, that is called rea- sonable. �And even where the testimony is contradictory, so much more credit may be due to one side than the other, that the same resuit will be produced. �On the other hand, the opposing proofs may be so nearly balanced that the jury may justly doubt on which side lies the truth, and, in such case, the accused party is entitled to the benefit of the doubt. �As certainty advances, doubt recedes. If one is reasonably cer- tain, he cannot, at the same time, be reasonably doubtful.i. e., have a reasonable doubt, of a fact. AU that a jury can be expected to do is to be reasonably or morally certain of the fact which they declare by their verdict. �As Chief Justice Shaw says, in Com. v. Webster, 5 Cush. 320 : �" For it is not sufflcient to establish a probability, though a strong one, aris- ing from the doctrine o£ chances, that the fact charged is more likely to be true than the contrary ; but the evidence must establish the truth of the fact to a reasonable and moral certainty; a certainty that convinces and directs the understanding, and satisfies the reason and judgment of those who are bound to act conscientiously upon it." �With regard to the evidence in this case, very little comment is required from the court, except upon one question, the others being hardly matters of dispute. �That the defendant fired at and shot the deceased president is abundantly proved, if you believe the testimony. ��� �
