Interesting how some think that when God told the man and woman to fill the Earth and multiply that some individuals believe that this precludes copulating.
And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth. (Gen 1:28)
The suggestion that Adam and Eve rose (rather than fell) when they ate of the fruit of the tree of knowledge of good and evil from a biblical viewpoint and, therefore, from a Christian viewpoint is Satanic. This is the cult of Lucifer (LSD or LDS). Christians are Christians. Those who are anything else other than Christians do not have the blessing of Lord Jesus Christ. Christians point to and glorify Lord Jesus Christ and do not introduce any material that talks of another way—another Gospel (Acts 16:17; Acts 24:14).
Not to know good and evil today is impossible unless one is born in a jungle or on a tropical island where people do not do harm to each other. However, this proposition precludes the observation that death and suffering and natural destructive forces are evil phenomena that drastically affect lives in locations where this is possible.
The Garden of Eden account could be a description of Earth untouched by the forces of nature that we see around us today. The implication is that Earth was a paradise cocooned within its surrounding Universe. However, good and evil is about morality and not so much the forces of nature. The idea that Adam and Eve were not capable of thinking (as the question implies within its assumption) before they disobeyed God is false. They could have reasoned that God had provided a directive to them not to eat of the tree of the prohibited fruit for good reasons. In fact, they could have even asked Him. The idea that the fall was the plan of God is to impute evil to the Righteous One and belongs only to ignorant people who do not know the Father, because they do not know the Son (Matt 11:27).
Isaiah (1:18) speaks of God desiring us today to come and reason with Him. Of course, seeking an audience with God wherein He responds is not something that many achieve. However, it is possible. I have sought God and He responded. But as I have learned after the event, my reasons for seeking God we acceptable to Him. There was no pretentiousness in my seeking God at the time (whereas today, if I were to do such a thing, there might be, because circumstances are different).
Evidently, those who are pretentious in any way are not acceptable to the One Who searches the hearts of people. You have to be genuine. Not just think you are genuine, but be as genuine as one who sees circumstances as a matter of life and death. Even then, you need reasons, such as hating evil. Most people are inclined to justify their evil actions. God looks for those who hate evil.
Those who hate evil, know what is evil and usually have yet to commit willful evil. However, people (as Saul of Tarsus did) hate evil but find themselves doing the evil they hate. This is because of the god of this world controls and influences people towards doing evil. To quote the converted Saul, who is now the Apostle Paul, speaking about his past life before becoming a Christian:
For I do not do the good I want, but the evil I do not want is what I do.... So I find it to be a law that when I want to do right, evil lies close at hand....Wretched man that I am! Who will deliver me from this body of death? Thanks be to God through Jesus Christ our Lord! (Romans 7:19, 21, 24-25a)
We qualify also as acceptable persons when we are prepared commit evil onlyif we know for sure God does not exist—for then there is no fear of eternal judgment—yet before we commit evil, which we would rather not do, we seek out the Judge beforehand to see whether He does exist. In God's grace and mercy, if we are life-and-death genuine, we shall be heard.
What has surprised me is that all this is in the Bible. In fact, the book of Wisdom teaches that the beginning of wisdom is the fear of the Lord and the fear of the Lord is hatred of evil (Proverbs 9:10; 8:13). In which case, the Christian or anyone who desires the truth can seek God and discover eternal reality, if they develop a genuine hatred of evil in all its forms, and desire assistance to overcome it because they know they are weak. The Bible tells us assistance shall be provided to every individual who so desires to overcome evil and who has the faith to reach out to God regardless of circumstances (Romans 5:1-10).