The Celtic Tree of Life
The concept of a tree of life has been used in science, religion philosophy, and mythology. A tree of life is a common motif in various world theologies, mythologies, and philosophies. It alludes to the interconnection of all life on our planet and serves as a metaphor for common descent in the evolutionary sense. The term tree of life may also be used as a synonym for sacred tree.
The tree of knowledge, connecting to heaven and the underworld, and the tree of life, connecting all forms of creation, are both forms of the world tree or cosmic tree, according to the Encyclopædia Britannica, and are portrayed in various religions and philosophies as the same tree.