The tree of the knowledge of good and evil is one of two specific trees in the story of the Garden of Eden in Genesis 2–3, along with the tree of life. Alternatively, some scholars have argued that the tree of the knowledge of good and evil is just another name for the tree of life.

In Christian tradition, consuming the fruit of the tree of knowledge of good and evil was the sin committed by Adam and Eve that led to the fall of man in Genesis 3.

In Catholicism, Augustine of Hippo taught that the "tree" should be understood both symbolically and as a real tree – similarly to Jerusalem being both a real city and a figure of Heavenly Jerusalem. Augustine underlined that the fruits of that tree were not evil by themselves, because everything that God created "was good" (Genesis 1:12). It was disobedience of Adam and Eve, who had been told by God not to eat of the tree (Genesis 2:17), that caused disorder in the creation, thus humanity inherited sin and guilt from Adam and Eve's sin.

In Western Christian art, the fruit of the tree is commonly depicted as the apple, which originated in central Asia. This depiction may have originated as a Latin pun: by eating the mālum (apple), Eve contracted malum (evil).

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