The tree, another symbol of knowledge (like the forbidden fruit tree, the tree of promised immortality or the tree of sin) once planted in the middle of the earthly paradise, is uprooted and forms the mast of the ship of fools, as can be seen in the engraving that illustrates Josse Bade's Stultiferae Naviculae, and doubtless it is the same tree that sways around above Bosch's Ship of Fools.