consciousness. This includes overcoming influences of both heredity and environment: "To be free is to be capable of thinking one's own thoughts – not the thoughts merely of the body, or of society, but thoughts generated by one's deepest, most original, most essential and spiritual self, one's individuality." Steiner affirms Darwin's and Haeckel's evolutionary perspectives but extended this beyond its materialistic consequences; he sees human consciousness, indeed, all human culture, as a product of natural evolution that transcends itself. For Steiner, nature becomes self-conscious in the human being. Steiner's description of the nature of human consciousness thus closely parallels that of Solovyov. Spiritual science In his earliest works, Steiner already spoke of the "natural and spiritual worlds" as a unity. From 1900 on, he began lecturing about concrete details of the spiritual world(s), culminating in the publication in 1904 of the first of several systematic presentations, his Theosophy: An Introduction to the Spiritual Processes in Human Life and in the Cosmos. As a starting point for the book Steiner took a quotation from Goethe, describing the method of natural scientific observation, while in the Preface he made clear that the line of thought taken in this book led to the same goal as that in his earlier work, The Philosophy of Freedom. In the years 1903–1908 Steiner maintained the magazine Lucifer-Gnosis and published in it essays on topics such as initiation, reincarnation and karma, and knowledge of the supernatural world. Some of these were later collected and published as books, such as How to Know Higher Worlds (1904–5) and Cosmic Memory. The book An Outline of Esoteric Science was published in 1910. Important themes include: the human being as body, soul and spirit; the path of spiritual development; spiritual influences on world-evolution and history; and reincarnation and karma. Steiner emphasized that there is an objective natural and spiritual world that can be known, and that perceptions of the spiritual world and incorporeal beings are, under conditions of training comparable to that required for the natural sciences, including self-discipline, replicable by multiple observers. It is on this basis that spiritual science is possible, with radically different epistemological foundations than those of natural science. He believed that natural science was correct in its methods but one-sided for exclusively focusing on sensory phenomena, while mysticism was vague in its methods, though seeking to explore the inner and spiritual life. Anthroposophy was meant to