Actually, I have heard this one a number of times. We don't know why God put that particular tree in the Garden. I am content to believe that as a mere human, I don't need to know Everything that God does and why. If I did, he wouldn't be a God to worship. He did tell Adam he would surely die and he did. In the 21st century we have a bad way of trying to interpret history thru this time and our current knowledge. How do you know they were to die? How do you know it was their destiny to die? Remember we don't get to see the behind the scenes of God yet! I for one can't wait until that day!! The bible is the truth, literally and you can believe it from cover to cover. We ALL face spiritual blindness until we take that step and except Jesus as Lord and Savior!!