Panpsychism is found in religions such as Shinto, Taoism, Paganism and Shamanism and pre-Socratic Greek philosophy. For example, Thales (c. 624 – 545 BCE) posited a theory which held "that everything is full of gods." Other Greek thinkers include Anaxagoras (who saw the underlying principle or arche as nous or mind) along with Anaximenes and Heraclitus.
Plato argues for Panpsychism in his Sophist, and in the Philebus and Timaeus, Plato where he claims there is a world soul or anima mundi. Hellenistic philosophies such as Neoplatonism andGnosticism also made use of the Platonic idea of the Anima mundi.
Panpsychism enjoyed something of an intellectual revival, in the thought of figures such as Gerolamo Cardano, Bernardino Telesio, Francesco Patrizi, Giordano Bruno, and Tommaso Campanella. Cardano argued for the view that soul or anima was a fundamental part of the world and Patrizi introduced the actual term "panpsychism" into the philosophical vocabulary. According to Giordano Bruno: "There is nothing that does not possess a soul and that has no vital principle." Platonist ideas like the anima mundi also resurfaced in the work of esoteric thinkers like Paracelsus, Robert Fludd andCornelius Agrippa.
Baruch Spinoza and Gottfried Leibniz were rationalists in the 17th centurny were panpyschists In Spinoza's monism, the one single infinite and eternal substance was "God, or Nature" (Deus sive Natura) which has the aspects of mind (thought) and matter (extension). Leibniz' view is that there are an infinite number of absolutely simple mental substances called monads which make up the fundamental structure of the universe. The Idealist philosophy of George Berkeley is also a form of pure panpsychism and technically all idealists can be said to be panpsychists by default.
In the 19th century, Panpsychism was at its zenith. Philosophers like Arthur Schopenhauer, Josiah Royce, William James, Eduard von Hartmann, F.C.S. Schiller, Ernst Haeckel and William Kingdon Clifford as well as psychologists like Gustav Fechner, Wilhelm Wundt and Rudolf Hermann Lotze all promoted Panpsychist ideas.
Arthur Schopenhauer argued for a two-sided view of reality which was both Will and Representation (Vorstellung). According to Schopenhauer: "All ostensible mind can be attributed to matter, but all matter can likewise be attributed to mind". Josiah Royce, the leading American absolute idealist held that reality was a "world self", a conscious being that comprised everything, though he didn't necessarily attribute mental properties to the smallest constituents of mentalistic "systems". The American Pragmatist philosopher Charles Sanders Peirce espoused a sort of Psycho-physical Monism which the universe as suffused with mind which he associated with spontaneity and freedom. Following Pierce, William James also espoused a form of panpsychism.
In the 20th century, the most significant proponent of the Panpsychist view is arguably Alfred North Whitehead (1861-1947). Whitehead's ontology saw the basic nature of the world as made up of events and the process of their creation and extinction. These elementary events (which he called occasions) are in part mental. According to Whitehead: "we should conceive mental operations as among the factors which make up the constitution of nature." Bertrand Russell's neutral monist views also tended towards panpsychism.
The psychologist Carl Jung, who is known for his idea of the collective unconscious, wrote that "psyche and matter are contained in one and the same world, and moreover are in continuous contact with one another", and that it was probable that "psyche and matter are two different aspects of one and the same thing".