Old Testament scholar Douglas Stuart has a short article on biblicaltraining.org in which he attempts to explain the meaning of the tree of the knowledge of good and evil. In short, Stuart argues that the term is a merism—a figure of speech in which two extremes are named in order to encompass everything in between. For example, if we say that a piece of news has spread “to the four corners of the earth,” we mean that the news has spread everywhere. That is a merism. So Stuart suggests that what the tree of the knowledge of good and evil represents, and what the serpent tempted Adam and Eve with, was omniscience. The actual effect, Stuart thinks, is that after eating the fruit:
The idea is that we now have more knowledge than we can morally handle. That is the point of what is emphasized here in this story. Part of the human dilemma as a consequence of the fall is that humans have enormous knowledge of how to do bad things as well as how to do good things.
Stuart seems to take it that the fruit literally imparts informational knowledge in some way, like a download. I do not know to what extent Stuart’s view represents a majority opinion, but I think there is a better explanation available.
“Knowing Good and Evil” Means Making Judgments
The first thing to say is that “knowing good and evil” does not refer to the possession of information, like one would “know” the capital of Belgium or the chemical components of a cell membrane. It is an active phrase, and refers to discernment between good and evil, or more simply, making judgments.
Compare for example the woman of Tekoa’s words to King David, when she was looking for him to correct a wrong:
“For the king will hear and deliver his maidservant from the hand of the man who would destroy both me and my son from the inheritance of God.” Then your maidservant said, “Please let the word of my lord the king be comforting, for as the angel of God, so is my lord the king to discern good and evil” (2 Samuel 14:16-17).
The woman is here seeking for the king to issue a judgment in her behalf. She associates this “knowledge” to the activity of God himself, or the “Angel of God.” It is the kind of judgment that is associated with rulership. Similarly, when Solomon became king upon David’s death, he prays for wisdom. But listen to his actual words:
And now, O Yahweh my God, you have made your servant king in place of David my father, although I am but a little child. I do not know how to go out or come in. And your servant is in the midst of your people whom you have chosen, a great people, too many to be numbered or counted for multitude. So give your servant a hearing heart to judge your people, to discern between good and evil. For who is able to judge this great people of yours? (1 Kings 3:9).
“Knowing Good and Evil” Represents Moral Maturity
Solomon’s request comes alongside his confession that he is like “a little child” (v. 7), and this points us to the second aspect of “the knowledge of good and evil.” It is associated with maturity—the type of maturity that is required to be a position of issuing moral judgments. To lack it is to be immature, or like a child. This is what God said of the children of the wilderness generation, before their entrance into Canaan:
Moreover, your little ones who you said would become a prey, and your sons, who this day have no knowledge of good or evil, shall enter there, and I will give it to them and they shall possess it (Deuteronomy 1:39).
To lack this knowledge is not morally blameworthy in an immature child; it is simply natural. At the same time, for those who should be further along in wisdom, knowledge of good and evil is expected. Listen to the author of Hebrews’ rebuke to his readers:
For though by this time you ought to be teachers, you have need again for someone to teach you the elementary principles of the oracles of God, and you have come to need milk and not solid food. For everyone who partakes only of milk is not accustomed to the word of righteousness, for he is an infant. But solid food is for the mature, who because of practice have their senses trained to discern good and evil (Hebrews 5:12-14).
Bringing this back to the tree in the garden, we can say that the name “the knowledge of good and evil” did not signify that this was a magic tree that one could eat from and have informational knowledge automatically implanted. The temptation was not to achieve omniscience. The name instead represents discerning activity that Adam was to exemplify and attain. In the above passage, Hebrews uses the image of food, and this is suggestive: The fruit of the tree was to be food for Adam along with the rest of the trees if he were to grow in wisdom and maturity and demonstrate the capacity to truly discern and judge between good and evil. In the first instance, that would mean obeying God’s simple commands. The tree was the testing point, to see if and in what way Adam would become one who “knows good and evil.”
What Did The Tree Mean?
Concretely, the tree represented for Adam the choice between submitting to God’s law or pursuing moral autonomy: Fearing the Lord (the beginning of wisdom), or judging for himself what good and evil are. Learning obedience would result in greater wisdom, maturity, and freedom. That is what the serpent tempted Adam and Eve with: “You shall be as gods, knowing good and evil” (Genesis 3:5). That is, you shall judge for yourselves. You will no be in the position of children, having good and evil dictated to you. The serpent tempted Adam and Eve with the prerogatives of autonomous, mature adulthood, before they had learned submission to God—and he tempted them to achieve this by way of disobedience. But it is important to understand that it could have been achieved with obedience as well, without the consequences of sin—and that is the tragedy. Adam and Eve were indeed destined to rule creation. Becoming like gods was not a bad thing or a bad desire. But this was to be achieved in the same way the rule of Jesus was achieved—by submission to God (Philippians 2:8-9).
Note also, “good and evil” here is probably a broader category than just morality. The immediate antecedent is God’s judgment over his creation in Genesis 1: “God saw that it was good.” This is not a question of the moral uprightness of the moon and plants and fishes. It is “good” in the sense of “fitting” or “beautiful.” The tree, as the testing point of Adam’s obedience, would also be the opportunity for him to exercise his judgment with regard to what is proper and fitting. One thing that was very unfitting in Adam’s action was that he allowed himself to be drawn away and made subservient to the serpent, a “beast of the field” (Genesis 3:1), a creature that God had given Adam and Eve a commission to exercise dominion over.
So an immediate effect of Adam and Eve’s sin was that their eyes were opened, and they saw that they were naked. Having acted out of accord with truth, goodness, and beauty by stepping outside of God’s command and seeking autonomy for themselves, all the while submitting to a creature who they should ruler over, they recognized their exposure and vulnerability, and their lack of glory. Clothing in the Bible represents glory, and Adam and Eve realized that in their immaturity they had reached for a godlikeness that they were not ready for, because they had not learned obedience. Adam and Eve were like little kids who want mommy and daddy’s tools and devices, and upon getting them, realize they do not know what to do with them and simply end up hurting themselves.
Paul says, “The heir, as long as he is a child, is no different from a slave, though he is owner of everything, but he is under guardians and stewards until the date set by his father” (Galatians 4:1-2). This was Adam and Eve’s position exactly. They were children, in the position of servants, having not yet entered the promised inheritance. They first needed the schoolmaster of the law. Their obedience to God would have issued in greater freedom and greater glory, and being trained in righteousness, righteousness and not sin is what they would have used their freedom to pursue (cf. Galatians 5:13). They would have understood that submission to God’s rule is good and fitting—and thus humbling themselves, they would have been exalted.
Having stepped out and grasped at this glory however, they did achieve a kind of maturity of experience, and so God acknowledges that “the man has become like one of us, knowing good and evil” (Genesis 3:22), though it was in a tragic manner. He also clothes them in recognition of this.
God laid a temporary prohibition on his children, who were set to grow into wise, mature, and free adulthood by way of obedience. They were to become like gods, judging between good and evil, and the tree was an opportunity to train them in this. However, the serpent tempted them with seizing this prerogative prematurely, by way of rebellion. Adam and Eve did judge between good and evil, but their act of judgment was flawed and proved fatal.
 In Genesis 1:29, God told the man and woman both that “every tree which has fruit yielding seed; it shall be food for you.” The prohibition on the tree of the knowledge of good and evil comes in ch. 2 and is given to Adam only, before Eve’s creation. Putting those facts together, we can assume that the prohibition on the tree was only temporary.
 This is why Adam and Eve had no shame in their nakedness. In their immature, childlike state, it was innocent. It was not God’s intention that they remain in that condition—the saints in heaven after all are given white robes of glory. They are not naked.
 It is sometimes suggested that God’s clothing of Adam and Eve represents an atonement or sacrifice for their sin, since clothing them with skins would require the death of an animal. However, the emphasis is entirely on the act of clothing—an image of investiture. Nothing is said about slaying an animal, blood, or anything having to do with sacrifice.