What is Idealism?
Idealism is the philosophical theory that reality is essentially mental or spiritual. Idealism is opposed to materialism, the theory that reality is physical. In philosophy there are two schools of idealism. The older school, which began with the ancient Greek philosopher Plato, is called objective idealism. It maintains that reality consists of ideal, immaterial forms existing outside the mind and that the material world is merely a pale reflection of the ideal world. Philosophers of the school of subjective idealism, on the other hand, maintain that reality exists only in the mind and that what are known as physical objects have no existence outside the mind.
The major philosophers of subjective idealism were Bishop George Berkeley (1685-1753) and David Hume (1711-1776). As a student at Trinity College in Dublin, Berkeley studied the works of John Locke (1632-1704), which greatly influenced the development of his idealistic theories. Locke had held that a distinction can be made between what he considered the primary qualities of an object, such as its size, shape, and motion, and its secondary qualities, such as color, odor, and taste. He claimed that only the primary qualities belong to the object. The secondary qualities exist in the mind of the person perceiving the object. A rose has a certain size and shape, but without an eye to perceive them it has no color.
Berkeley carried Locke's theory further and contended that both primary and secondary qualities exist in the mind. If one imagines seeing an apple hanging from a limb, he is certain only of the sensation and of the idea aroused in his mind of an apple and a limb. He is not at all certain of the actual existence of the objects. Whereas Locke had maintained that notions about an object originated in the object, Berkeley denied the very existence of the object. He concluded that reality consists only of minds and their ideas and that these ultimately depend on the mind of God.
The Scottish philosopher David Hume pressed subjective idealism to its logical conclusion. He maintained that if he could not posit the existence of objects, he could not believe in the existence of other minds. If he rigorously applied Berkeley's theory, he would have to exclude everything but the one fact of his own mental existence. This extreme position is called solipsism. Hume claimed the objective realist would have to deny even the existence of his own mind and affirm his own existence as being no more than a chain of sensations or impressions.
Hume's skeptical position inspired the German philosopher Immanuel Kant (1724-1804) to find a way out of the dilemma. Kant claimed that knowledge does not come wholly through experience, but that the mind has to impose forms on nature before man can understand his experiences. He emphasized the structure of nature, rather than its qualities. He held that certain forms, such as those of space and time, are not to be found in nature or through experience and that they must therefore arise in the mind. Kant was thus able to affirm the mind's existence. However, Kant was not a thoroughgoing idealist. He believed that objects exist physically outside the mind, but he claimed that man can never fully understand the essential nature of objects. Kant called this his thing-in-itself theory. Kant's theories concerning logic and mathematics and such forms as space and time led to objective idealism, which is the theory that forms exist independent of man.
The German philosopher Georg W. F. Hegel (1770-1831) used Kant's theories to »the the objective existence of nature. Hegel an idealist in that he stressed the spiritual char-of the world. Unlike Berkeley and Hume, he maintained that much of what is real lies outside the mind and that the individual human mind is only a fragment of the Absolute, or the all-embracing realm of Spirit. Hegel further contended that the world must be an intelligible system in order to be understood. His central doctrine is that "the real is rational", or that the world is a logical system and philosophy is the attempt by the human mind to understand it.
Hegel's philosophy led to several conclusions, one of which was determinism, the belief that nothing happens merely by chance. Another belief is that the nature of an object can be understood only by comprehending its relation to the whole reality, called the Absolute.
Other objective idealists who followed Hegel were the British philosophers Thomas Hill Green '1836-1882) and Francis Herbert Bradley (1846-1924), the American philosopher Josiah Royce (1855-1916), and the Italian philosopher Benedetto Croce (1866-1952).