Who decides what is good and bad? According to the Bible, God does;
(Genesis 2:16-17) 16And Jehovah God also laid this command upon the man: "From every tree of the garden you may eat to satisfaction. 17 But as for the tree of the knowledge of good and bad you must not eat from it, for in the day you eat from it you will positively die.". . .
However, another player in the story argues that we each need to decide for ourselves what is good and what is bad;
(Genesis 3:4-5) 4At this the serpent said to the woman: "YOU positively will not die. 5 For God knows that in the very day of YOUR eating from it YOUR eyes are bound to be opened and YOU are bound to be like God, KNOWING good and bad."
Let's assume for the moment that God decides what is good and bad.
Does He [a] choose what is good because it is obviously good or [b] is it good because He says so?
If 'a' then what is good is independant of God and He has no choice but to accept it as good. If 'b' then the definition of what is good is arbitrary - God could decide that child abuse was good and it would be because He said so. Clearly this is ridiculous because we all recognise child abuse to be a bad thing and that is why God would never label it as good.
To recognise this however is to accept that we do not need God to determine for us what is good and what is bad.
(Genesis 3:6-7) . . .So she began taking of its fruit and eating it. Afterward she gave some also to her husband when with her and he began eating it. 7Then the eyes of both of them became opened . . .