were the objections to his Meditations on First Philosophy (1641), published with the text. Also important to the later development of psychology were his Passions of the Soul (1649) and Treatise on Man (completed in 1632 but, along with the rest of The World, withheld from publication after Descartes heard of the Catholic Church's condemnation of Galileo; it was eventually published posthumously, in 1664). Although not educated as a physician, Descartes did extensive anatomical studies of bulls' hearts and was considered important enough that William Harvey responded to him. Descartes was one of the first to endorse Harvey's model of the circulation of the blood, but disagreed with his metaphysical framework to explain it. Descartes dissected animals and human cadavers and as a result was familiar with the research on the flow of blood leading to the conclusion that the body is a complex device that is capable of moving without the soul, thus contradicting the "Doctrine of the Soul". The emergence of psychology as a medical discipline was given a major boost by Thomas Willis, not only in his reference to psychology (the "Doctrine of the Soul") in terms of brain function, but through his detailed 1672 anatomical work, and his treatise ("Two Discourses on the Souls of Brutes"—meaning "beasts"). However, Willis acknowledged the influence of Descartes's rival, Pierre Gassendi, as an inspiration for his work. The philosophers of the British Empiricist and Associationist schools had a profound impact on the later course of experimental psychology. John Locke's An Essay Concerning Human Understanding (1689), George Berkeley's Treatise Concerning the Principles of Human Knowledge (1710), and David Hume's A Treatise of Human Nature (1739–1740) were particularly influential, as were David Hartley's Observations on Man (1749) and John Stuart Mill's A System of Logic. (1843). Also notable was the work of some Continental Rationalist philosophers, especially Baruch Spinoza's (1632–1677) On the Improvement of the Understanding (1662) and Gottfried Wilhelm Leibniz's (1646–1716) New Essays on Human Understanding (completed 1705, published 1765). Another important contribution was Friedrich August Rauch's (1806–1841) book Psychology: Or, A View of the Human Soul; Including Anthropology (1840), the first English exposition of Hegelian philosophy for an American audience. German idealism pioneered the proposition of the unconscious, which Jung considered to have been described psychologically for the first time by physician and philosopher Carl Gustav Carus. Also notable was its use by Friedrich Wilhelm Joseph von Schelling (1775-1835), and