Acts 1:3 To whom also he shewed himself alive after his passion by many infallible proofs,
In US courts we have various standards for decisions made by jurors. In criminal cases a verdict of guilty cannot be returned unless the juror is sure of guilt “beyond a reasonable doubt”. This means that the evidence presented to the juror has established a particular point to a moral certainty, and it is beyond dispute that any reasonable alternative is possible. But “beyond a reasonable doubt” does not mean absolute proof or the absence of any doubt.
In civil cases there is the standard of “proof by clear and convincing evidence.” This is a lower burden of proof than reasonable doubt. It is a decision by the Juror that there is high probability that “a fact sought to be proved is true.”
In the language of the New Testament a word of evidence and decision making was used in this verse. It is translated “infallible proofs”. The Greek scholars in Friberg’s Analytical Greek Lexicon defined this word as: “evidence that removes doubt.” This is the highest level of proof: these people witnessed the same reality over, and over, and over again, to the point that they could not mistake the truth of what they had witnessed. The proof was absolute. This word was used here by Luke concerning the resurrection of Jesus Christ.