René Descartes (1596-1650) is best known for his statement on the link between thought and existence: 'Cogito, ergo sum'. A renowned mathematician, philosopher and scientist, Descartes was born in France, but spent some 20 years living in the Dutch Republic, serving in the Dutch States Army of Maurice of Nassau. In addition to Meditations on First Philosophy, he is also known for Discourse on the Method (1637) and Principles of Philosophy (1644).

Frank Sewall (1837-1915) was an American Swedenborgian clergyman with a keen interest in metaphysical philosophy. His publications include The New Metaphysics (1888), Swedenborg and Modern Idealism (1902) and the introduction and notes to Emanual F. Gorqitz's translation of Immanuel Kant's Dreams of a Spirit-Seer (1900).