Something in the world of the senses, including an action, that manifests (reveals) or signifies (is a sign for or a pointer to) a thing, or what is abstract, otherworldly, or numinous. Samuel Johnson (1755) termed it "A type; that which comprehends in its figure a representation of something else." A word denotes, refers to, or labels something in the world, but a symbol, as a thing in the world (to which a word, of course, may point), has a concreteness not shared by language and points to something, often what transcends ordinary experience. Any tree, for example, arguably symbolizes tree-ness, a Platonic form. Any image or action termed a Jungian archetype is also symbolic in that it manifests something in the collective unconscious of human beings. Writers often use symbols when they believe in a transcendental reality. A metaphor compares two or more things that are no more and no less real than anything else in the world. For a metaphor to be symbolic, one of its pair of elements must manifest or reveal yet something else transcendental. Cleanth Brooks and Robert Penn Warren in Understanding Poetry (3rd edn., 1960), however, say that "The symbol may be regarded as a metaphor from which the first term has been omitted" (556).