At the moment that Adam decided to disobey God, he was no longer innocent. He experienced, for the first time, shame, guilt, and fear. When He ate of the forbidden fruit, he proved that the tree was as "advertised." He gained knowledge which produced evidence of wisdom. Psalms 111:10, Proverbs 1:7, and 9:10 teach us that fear is the beginning of knowledge and wisdom. The tree in question didn't make Adam smarter or wiser; what it did do was cause him to fear God. His response demonstrated that he now had a conscience. Every human born since that day has a conscience. A conscience is a good thing, in that it produces awareness of sin of which one needs to repent. A conscience is also able to affirm one's actions (Acts 24:16). Even unbelievers benefit from having a conscience, because it makes them aware of right and wrong (Romans 2:15). The problem with one's conscience being their guide, as is so often recommended, it can become seared or made impotent, so that nothing is beyond them concerning sin.
The Dispensation of Conscience began because of sin, and it ended for the same reason. Not long after the Fall, the first murder occurred. Cain killed his brother (Genesis 4:8). It was all down hill from there. By the time Noah was born, man had become so evil that God repented of having created them (Genesis 6:6). "And God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only on evil continually." (Genesis 6:5). It was obvious that one's conscience was not sufficient to prevent sin. God was gracious toward Noah, and decided to show mercy on a remnant of eight souls. God waited long enough for Noah to build the "escape module" and then He destroyed every living, breathing creature on the planet. This judgment is known as The Flood.
The Dispensation of Conscience might be described as follows:
Stewardship: Provide for the needs of one's family (Genesis 3:17-19)
Foods: Crops and wild plants (compare Genesis 3:17-19 with Genesis 6:21)
Command: Do the right thing (Genesis 4:1-7)
Response: Total depravity (Genesis 6:5)
Judgment: THE FLOOD At least the physical death of all but eight souls (1 Peter 3:20)