considered the foundational text of classical economics. Scientific discovery would accelerate in the late modern period, and continues today. Technology Inventions of the early modern period included the floating dock, lifting tower, newspaper, grenade musket, lightning rod, bifocals, and Franklin stove. Early attempts at building a practical electrical telegraph were hindered because static electricity was the only source available. Enlightenment and reason The Age of Enlightenment is also called the Age of Reason because it marked a change from the medieval tradition of scholasticism based on Christian dogma and the often occultist approach of Renaissance philosophy. Instead, reason became the central source of knowledge, beginning the era of modern philosophy, especially in Western philosophy. The period was typified in Europe by the great system-builders, philosophers who presented unified systems of epistemology, metaphysics, logic, and ethics and often politics and the physical sciences as well. Early 17th-century philosophy is often called the Age of Rationalism and is considered to succeed Renaissance philosophy and precede the Age of Enlightenment, but some consider it as the earliest part of the Enlightenment era in philosophy, extending that era to two centuries. This era includes Isaac Newton's Principia and René Descartes' "I think therefore I am" (1637). The 18th century saw the beginning of secularization in Europe, rising to notability in the wake of the French Revolution. Immanuel Kant classified his predecessors into two schools: the rationalists and the empiricists, The three main rationalists are normally taken to have been René Descartes, Baruch Spinoza, and Gottfried Leibniz. Roger Williams founded Providence Plantations in New England, based on the principle of separation of church and state after being exiled by Puritans in the Massachusetts Bay Colony. The Enlightenment began at Harvard in 1646. The first great advances towards modern science were made in the mid-17th century, most notably the theory of gravity by Isaac Newton (1643–1727). Newton, Spinoza, John Locke (1632–1704) and Pierre Bayle (1647–1706) were philosophers sparking the ideas for the furthering of the Enlightenment. French salon culture culminated in the Enlightenment's most influential publication, the great Encyclopédie (1751–1772), edited by Denis Diderot (1713–1784) with contributions by hundreds of leading philosophes (intellectuals) such as Voltaire (1694–1778) and Montesquieu (1689–1755). The Quarrel of the Ancients and the Moderns shook up the French Academy in the 1690s, elevating new discoveries over Greek and Roman wisdom. The French Enlightenment was received in Germany, notably fostered by Frederick the