What is the Tree of Knowledge of Good and Evil?

Genesis 2:15-17
15 And the Lord God took the man, Adam, and put him into the garden of Eden to dress it and to keep it.
16 And the Lord God commanded the man, saying, Of every tree of the garden you may freely eat:
17 But of the tree of the knowledge of good and evil, you shall not eat of it: for in the day that you eat of it you shall surely die.

Just what is the “Tree of the Knowledge of Good and Evil?”  Is it a real tree, or is the tree just a symbol?  Manasseh says it is a symbol, and I hope he will put his comments here about it.  I also think it is a symbol, but a symbol of what?

Genesis 3:1-13
Blessings….c


Here is a thought I have, it may or may not be related.  What were Adam and Eve before they sinned by eating the fruit of this tree?  They were innocent, their eyes were protected from seeing anything wrong or evil.  Maybe there was no wrong or evil around them.  But my thought here is, they were innocent and enjoyed the fellowship with one another and with God as children enjoy playing together with their best friend and the company of their loving parents.

Now the serpent was more subtile than any beast of the field which the Lord God had made. And he said unto the woman, Yea, has God really said, You shall not eat of every tree of the garden?

2 And the woman said unto the serpent, We may eat of the fruit of the trees of the garden:
3 But of the fruit of the tree which is in the midst of the garden, God has said, You shall not eat of it, neither shall you touch it, lest you die.
4 And the serpent said unto the woman, You shall not surely die:
5 For God does know that in the day you eat of it, then your eyes shall be opened, and you shall be as gods, knowing good and evil.
6 And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat.
7 And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons.
8 And they heard the voice of the Lord God walking in the garden in the cool of the day: and Adam and his wife hid themselves from the presence of the Lord God amongst the trees of the garden.
9 And the Lord God called unto Adam, and said unto him, Where are you?
10 And he said, I heard your voice in the garden, and I was afraid, because I was naked; and I hid myself.
11 And he said, Who told you that you were naked? Have you eaten of the tree, where I commanded you that thou should not eat?
12 And the man said, The woman whom thou gave to be with me, she gave me of the tree, and I did eat.
13 And the Lord God said unto the woman, What is this that you have done? And the woman said, The serpent beguiled me, and I did eat.

Here is the other part of my thought, and I will leave this as an open question and not put in the rest of my thought – because I want to see what others will write.  My question, “What is it, or what is something, that once introduced into a child’s life takes away their innocence?  Could this something possibly be related to the Tree of the Knowledge of Good and Evil?”
I will tell you my thoughts after I read some of yours…I am just curious as if someone will get the same thoughts as I have had this morning.
Love to you all and I’m looking forward to any replies.  :)