 This idea can be interpreted in either of two ways. The great classical philosophers—Plato, Aristotle, Spinoza, Descartes, Hobbes, Hume, Locke—all understood emotions to involve feelings understood as primitives without component parts. An alternative idea was first introduced by William James, who argued that scientific psychology should stop treating feelings as “eternal and sacred psychic entities, like the old immutable species in natural history” (James 1890: 449).