How was it that Bill Cosby described the scene? It’s been years since I heard the skit, but it went something like this:
Adam (thinking): A female. Drooolllll…
Eve (thinking): Oohhh. I can have some fun with this oaf.
Eve to Adam (aloud): "Here, honey. Eat this rock. Eat this dirt. Eat this fruit."
Adam to Eve (aloud): "Yeahhh. Slobberrr. Drooollll."
Now if you want to believe God made Adam that simpleminded, you could argue that Adam should be absolved of responsibility.
Personally, I find it hard to imagine that Adam would not know, at a minimum, what the Forbidden Fruit looked like. That way, when he found a piece on the ground near the tree, he would know to not eat it by accident.
Look back in Genesis at 2:15-25. First God put Adam in the garden. Then God told Adam “See that tree over there? Don’t eat the fruit from that tree.” After this, God created Eve. Who passed the message to Eve?
I’m quite sure that Adam knew exactly what he was doing. And he never said to Eve, “uhhh… there’s something strange about this.”