Baruch Spinoza was a Dutch philosopher who was also a lens grinder by trade. Spinoza was an independent and solitary thinker. He refused academic appointments and decided not to teach at the University of Heidelberg because he did not want to be confined by any established ideas of an academic institution.
Spinoza is most known for his promotion of monism, the idea that there is only one single substance in the world—God or nature (Deus sive Natura). This idea was contrary to the concept of dualism and its idea that reality was made of two substances—mind and matter. For Spinoza, mind and matter were two modes of the single substance—God/nature. Thus, there is no distinction between mind and matter, both are different manifestations of God/nature. With Spinoza’s monism, any statement about any object is a statement about God or nature. This view has often been linked with pantheism—the belief that God is nature and nature is God. Spinoza rejected belief in the immortality of the soul.
Educated as an orthodox Jew, Spinoza became unpopular with both Jews and Christians because of his unorthodox beliefs. Spinoza argued for a late dating of the Old Testament books and denied the miracles of the Bible. He was considered by some to be a closet atheist. In 1656, he was excommunicated from his Jewish community and synagogue in Amsterdam because of his unorthodox beliefs.
In 1677, Spinoza died from glass dust inhalation. After his death, his works were largely ignored and viewed as the dangerous works of a closet atheist. His ideas were eventually discovered by Lessing and he had a significant impact on the beliefs of Georg Hegel.