Did Adam know, when he ate it at Gen 3:6, that Eve had given him the forbidden fruit? In any event, what was Adam’s sin?

There is nothing in the Gen 3 text that settles the matter clearly. Adam is not mentioned in Gen 3 until this verse. It is possible that he was listening in while the serpent spoke to Eve; but it seems to me that such an important detail would be mentioned if true. It is also possible that he recognized the distinctive fruit, but perhaps not. And of course it is possible that Eve told him, before he ate the fruit, that it was the forbidden fruit and that she had eaten it. Elsewhere, however, Paul told Timothy, “Adam was not deceived, but the woman being deceived was in the transgression.” (1 Tim. 2:14) If Adam was not deceived, very well; but about what was he not deceived? Perhaps Paul means he was not deceived by the serpent. In that case, was it still possible that he could have been misled somehow, even if not deceived, by Eve’s encouragement and example? That seems to be what happened. If so, then he was influenced by her words and sinful example, and therefore indirectly manipulated (but not deceived) by the serpent. If Adam was not deceived at all, then it seems he ate trustingly and carelessly when Eve gave him the fruit. In that case, his error would not have been to willfully disobey, but to fail to ensure with due care that his wife had followed the one rule they had. It is indeed possible even in that case that God punished him as the head of the family and as the hapless, unwitting partaker of the sin. Regardless, it is interesting that Adam soon recognized his own role as sinful and shameful, whether willful or not, whether he knew the fruit he ate was the forbidden one, or not. I do not think the text makes it quite clear enough (or it is not clear to me, anyway), but my best guess for now is that Adam’s sin was carelessness and forgetfulness of God’s law. If that is correct, then when Eve offered the fruit, he simply did not care enough about the law to inquire about where it came from.