In The Everlasting Man, G.K. Chesterton addresses the question of repeated myths in human culture. His metaphor is an interesting one. While the soil might be the same for the oak tree and the chrysanthemum, this does invalidate the unique qualities of each plant.
I would undertake to find something like a bunch of flowers figuring again and again from the fatal bouquet of Becky Sharpe to the spray of roses sent by the Princess of Ruritania. But though these flowers may spring from the same soil, it is not the same faded flower that is flung from hand to hand. Those flowers are always fresh.
G.K. Chesterton
The literary critic does well to investigate the soil but should forget a description of each work’s unique fragrance.
Experiments in Criticism 