Modern Philosophy

A great cultural movement in Europe called the Renaissance overlapped the end of the Middle Ages and formed a transition between medieval and modern philosophy. The Renaissance began in Italy and lasted from about 1300 to about 1600. It was a time of intellectual reawakening stemming from the rediscovery of ancient Greek and Roman culture. During the Renaissance, major advances occurred in such sciences as astronomy, physics, and mathematics. Scholars called humanists stressed the importance of human beings and the study of classical literature as a guide to understanding life. Emphasis on science and on humanism led to changes in the aims and techniques of philosophic inquiry. Scholasticism declined, and philosophy was freed of its ties to medieval theology.

One of the earliest philosophers to support the scientific method was Francis Bacon of England. Most historians consider Bacon and Rene Descartes of France to be the founders of modern philosophy. Bacon wrote two influential works, The Advancement of Learning (1605) and Novum Organum (1620). He stated that knowledge was power and that knowledge could be obtained only by the inductive method of investigation. Bacon imagined a new world of culture and leisure that could be gained by inquiry into the laws and processes of nature. In describing this world, he anticipated the effects of advances in science, engineering, and technology.

Rationalism was a philosophic outlook that arose in the 1600's. The basic idea of rationalism is that reason is superior to experience as a source of knowledge and that the validity of sense perception must be proved from more certain principles. The rationalists tried to determine the nature of the world and of reality by deduction from premises themselves established as certain a priori. They also stressed the importance of mathematical procedures. The leading rationalists were Rene Descartes, Baruch Spinoza, and Gottfried Leibniz.

Descartes was a mathematician as well as a philosopher. He invented analytic geometry. Descartes's basic idea was to establish a secure foundation for the sciences, a foundation of the sort he had found for mathematics. He was thus much concerned with the foundations of knowledge, and he started philosophy on its persistent consideration of epistemological problems. Descartes was a mechanist--that is, he regarded all physical phenomena as connected mechanically by laws of cause and effect. Descartes's philosophy generated the problem of how mind and matter are related.

Spinoza constructed a system of philosophy on the model of geometry. He attempted to derive philosophic conclusions from a few central axioms (supposedly self-evident truths) and definitions. Spinoza did not view God as some superhuman being who created the universe. He identified God with the universe. Spinoza was also a mechanist, regarding everything in the universe as determined. Spinoza's main aim was ethical. He wanted to show how people could be free, could lead reasonable and thus satisfying lives, in a deterministic world.

Leibniz believed that the actual world is only one of many possible worlds. He tried to show how the actual world is the best of all possible worlds in an effort to justify the ways of God to humanity. Thus, he attempted to solve the problem of how a perfect and all-powerful God could have created a world filled with so much suffering and evil. Leibniz and Sir Isaac Newton, an English scientist, independently developed calculus. Leibniz' work in mathematics anticipated the development of symbolic logic--the use of mathematical symbols and operations to solve problems in logic.

Empiricism emphasizes the importance of experience and sense perception as the source and basis of knowledge. The first great empiricist was John Locke of England in the 1600's. George Berkeley of Ireland and David Hume of Scotland further developed empiricism in the 1700's.

Locke tried to determine the origin, extent, and certainty of human knowledge in An Essay Concerning Human Understanding (1690). Locke argued that there are no innate ideas--that is, ideas people are born with. He believed that when a person is born, the mind is like a blank piece of paper. Experience is therefore the source of all ideas and all knowledge.

Berkeley dealt with the question "If whatever a human being knows is only an idea, how can one be sure that there is anything in the world corresponding to that idea?" Berkeley answered that "to be is to be perceived". No object exists, he said, unless it is perceived by some mind. Material objects are ideas in the mind and have no independent existence.

Hume extended the theories of Locke and Berkeley to a consistent skepticism about almost everything. He maintained that everything in the mind consists of impressions and ideas, with ideas coming from impressions. Every idea can be traced to and tested by some earlier impression. According to Hume, we must be able to determine from what impression we derived an idea for that idea to have meaning. An apparent idea that cannot be traced to an impression must be meaningless. Hume also raised the question of how we can know that the future will be like the past--that the laws of nature will continue to operate as they have. He claimed that we can only know that events have followed certain patterns in the past. We cannot therefore be certain that events will continue to follow those patterns.

The Age of Reason was a period of great intellectual activity that began in the 1600's and lasted until the late 1700's. The period is also called the Enlightenment. Philosophers of the Age of Reason stressed the use of reason, as opposed to the reliance on authority and scriptural revelation.

For them, reason provided means of attaining the truth about the world and of ordering human society to assure human well-being. The leading philosophers included Descartes, Locke, Berkeley, and Hume. They also included Jean Jacques Rousseau, Voltaire, Denis Diderot, and other members of a group of French philosophers.

Locke's philosophic ideas were characteristic of the Age of Reason. Locke sought to determine the limits of human understanding and to discover what can be known within those limits that will serve as a guide to life and conduct. He tried to show that people should live by the principles of toleration, liberty, and natural rights. His Two Treatises of Government (1690) provided the philosophic base for the Revolutionary War in America and the French Revolution in the late 1700's.

The philosophy of Immanuel Kant, a great German philosopher of the late 1700's, became the foundation for nearly all later developments in philosophy. Kant's philosophy is called critical philosophy or transcendental philosophy.

Kant was stimulated by the skeptical philosophy of Hume to try to bring about a synthesis of rationalism and empiricism. In his Critique of Pure Reason (1781), Kant tried to provide a critical account of the powers and limits of human reason, to determine what is knowable and what is unknowable. Kant concluded that reason can provide knowledge only of things as they appear to us, never of things as they are in themselves. Kant believed that the mind plays an active role in knowing and is not a mere recorder of facts presented by the senses. The mind does this through basic categories or forms of understanding, which are independent of experience and without which our experience would not make sense. Through such categories and the operations of the mind, working on sense experience, we can have knowledge, but only of things that can be experienced.

Kant criticized the traditional arguments for the existence of God. He argued that they are all in error because they make claims that go beyond the possibility of experience and thus go beyond the powers of human reason. In his Critique of Practical Reason (1788), Kant argued that practical reason (reason applied to practice) can show us how we ought to act and also provides a practical reason for believing in God, though not a proof that God exists.