In Western civilization, Idealism is the philosophy which maintains that the ultimate nature of reality is ideal, or based upon ideas, values, essences: The so-called external, or real world is inseparable from consciousness, perception, mind, intellect and reason--in the sense of rigorous science. It is also the tendency in Western thought to represent things in an ideal form, or as they ought to be rather than as they really are, in the realms of ethics, morality, aesthetics, and value.
The philosophical schools of Western Idealism, and the history of Western philosophers, are different from those of the ancient and archaic East, which are for the most part steeped in religious and mystical creeds, devoid of any purely rational and scientific elements--in the classical Greek sense of Plato, Aristotle, and Euclid. Today it is difficult to draw an exact philosophical distinction between East and West because of the global influence of European and American scientific and technological education. In some doctrines of idealistic thought the ideal relates to direct and immediate knowledge of subjective mental ideas, or images. In the strife of the schools, sometimes idealism is opposed to realism in which the real is said to have absolute existence prior to and independent of our knowledge. Epistemological idealists (such as Kant) might insist that the only things which can be directly known for certain are ideas. In our day the anti-idealistic criticism of idealism is for the most part the result of 20th century prejudices against metaphysics, often combined with a speciously elaborated distinction between ontology and epistemology.
Plato is called an idealist because of his theory of Forms or doctrine of Ideas, which are "ideal" in the dictionary sense. Some interpreters hold that Plato does not describe the Forms as being in any mind, instead he describes them as having their own independent existence,--for which the textual evidence is adduced from various translations of the dialogues. Indeed, some anti-idealist commentators say that in the dialogues Socrates often denies the reality of the material world. However, it is clear that the Platonic Socrates merely denies the ideal reality of the non-ideal realm, namely the world of appearances, which he sometimes compares to shadows. An exact interpretation of the dialogues, which are notoriously misrepresented, involves knowledge of linguistics, hermeneutics, philology, semantics, and the philosophy of language, as well as good grounding in classical studies. Athenian Greek philosophical terms, like most English abstract nouns, have more than one meaning. It seems clear that Plato is not, at any rate, a subjective idealist, like Berkeley.
Plato's Allegory of the Cave is sometimes interpreted by anti-platonists as drawing attention to the modern European philosophical problem of knowing external objects--the question that is often attributed to Descartes, Locke, Berkeley, and other modernist philosophers. According to certain materialistic interpretations of Plato, which construe matter as an entirely external reality, the Forms that the Cave-dwellers are ignorant of are not external to them in the way that so-called material objects are for modern thinkers. Again, some anti-idealistic readers hold that for Plato the Forms are true realities, but they are not outside of us in a spatial sense like material objects, which some natural scientists call physical bodies. For these interpreters, one might say, the issue that Plato's allegory addresses is the problem of how one can know what is truly real and good--a theme which apparently is opposed to the so-called modern question of our knowledge of the external world.
However, speaking in the realm of pure abstract theory, even if Plato doesn't share the specific concerns of modern philosophy, and of George Berkeley, in particular, Plato could still be a non-subjective idealist. Plato could believe that matter has no so-called independent existence, that ultimate reality (distinct from mere appearance) is known only in the world of ideas--should we care to speculate in purely hypothetical terms. Bernard Williams and Myles Burnyeat have surmised that Greek philosophers never conceived of so-called idealism as an option, because they lacked Descartes's conception of an independently existing mind. Perhaps Williams and Burnyeat did not consider the apparent possibility that Plato could have held an idealism like Kant's, which appears to argue from the nature of knowledge to the nature of the objects of knowledge; or he might have subscribed to a form of Absolute Idealism, like that of G.W.F. Hegel which, say commentators, denies that matter is ultimately real--without perhaps (in either case) reducing so-called material objects to ideas in a mind or minds. Moreover, we conjecture, Plato's theory of the separation of soul and body could be seen as an earlier, primitive form of Cartesian dualism.
The German neo-kantian scholar, Paul Natorp, argued in his Plato's Theory of Ideas. An Introduction to Idealism (first published in 1903) that Plato was a non-subjective, "transcendental" idealist, somewhat like Kant. Natorp's thesis has received some support from commentators and neo-kantian scholars.
Similarly, professor Ludwig Noiré wrote: "For the first time in Western philosophy we find idealism proper in Plotinus (Enneads, iii, 7, 10), where he says, "The only space or place of the world is the soul," and "Time must not be assumed to exist outside the soul. It is worth noting, however, that like Plato but unlike Schopenhauer and other modern philosophers, Plotinus does not worry about whether or how we can get beyond our ideas in order to know external objects.
This subjective idealism or dogmatic idealism led to his placing the full weight of justification on our perceptions. This left Berkeley with the problem of explaining how it is that each of us apparently has much the same sort of perceptions of an object. He solved this problem by having God intercede, as the immediate cause of all of our perceptions.
Schopenhauer wrote: "Berkeley was, therefore, the first to treat the subjective starting-point really seriously and to demonstrate irrefutably its absolute necessity. He is the father of idealism...." (Parerga and Paralipomena, Vol. I, "Fragments for the History of Philosophy," § 12) Schopenhauer could have said, instead, that Berkeley was the "father" of the modern variety of idealism that is motivated, primarily, by epistemological considerations--as distinct from the more purely metaphysical idealism of (for example) Plotinus or Hegel. Bishop Berkeley therefore is considered the first modern philosopher known as an idealist. His immaterialism held that objects exist by the good quality of our perception of them. In other words, they are ideas residing in our awareness - as well as in the consciousness of the Divine Being.
Collier was influenced by John Norris's (1701) An Essay Towards the Theory of the Ideal or Intelligible World. The idealist statements by Collier were generally dismissed by readers who were not able to reflect on the distinction between a mental idea or image and the object that it represents.
Kant's postscript to this added that the mind is not a blank slate, tabula rasa, (contra John Locke), but rather comes equipped with categories for organising our sense impressions. Perhaps this Kantian sort of idealism opens up a world of abstractions (i.e., the universal categories minds use to understand phenomena) to be explored by reason, but perhaps, in sharp contrast to Plato's, confirms uncertainties about a (un)knowable world outside our own minds. We cannot approach the noumenon, the "Thing in Itself" (Ding an Sich) outside our own mental world. (Kant's idealism is called transcendental idealism.)
Apparently Kant distinguished his transcendental or critical idealism from previous varieties:
It is perhaps a noteworthy fact that some commentators of Hegel, even those who admire his philosophy, fail to distinguish hegelian idealism from either the philosophy of Berkeley or Kant. Hegel certainly intends to preserve what he takes to be true of German idealism, in particular Kant's insistence that ethical reason can and does go beyond finite inclinations. However, some commentators hold that Hegel does not endorse Kant's conception of the thing-in-itself, or the type of epistemological perplexities that led Kant to that view. Still less does Hegel endorse Berkeley's doctrine that to be is to perceive or to be perceived--in the purely Berkeleyian sense. The guiding ideal behind Hegel's absolute idealism is the scientific thought, which he shares with Plato and other great idealist thinkers, that the exercise of reason and intellect enables the philosopher to know ultimate historical reality, which in the hegelian system is the phenomenological constitution of self-determination,--the dialectical development of self-awareness and personality in the realm of History. By giving this Ideal a central role in his philosophy, Hegel made a lasting contribution to that part of the Western mindset, beginning in earnest with Plato and his presocratic predecessors, which makes Idealism the basis of civilization and progress in the world.
Schopenhauer's history is an account of the concept of the "ideal" in its meaning as "ideas in a subject's mind." In this sense, "ideal" means "ideational" or "existing in the mind as an image." He does not refer to the other meaning of "ideal" as being qualities of the highest perfection and excellence. In his On the Freedom of the Will, Schopenhauer noted the ambiguity of the word "idealism" by calling it a "term with multiple meanings."
It is evident that Schopenhauer's "idealism" is based primarily on considerations having to do with the relation between our ideas and external reality, rather than being based (like Plato's, Plotinus's, or Hegel's "idealism") on considerations having to do with the nature of reality as such.
Bradley was the apparent target of G. E. Moore's radical rejection of idealism. Moore claimed that Bradley did not understand the statement that something is real. We know for certain, through common sense and prephilosophical beliefs, that some things are real, whether they are objects of thought or not, according to Moore. In this way, he disagreed with Bradley's assertion that we cannot think of anything that really exists unless we have a thought of it in our mind.
J. M. E. McTaggart of Cambridge University, argued that minds alone exist, and that they only relate to each other through love. Space, time and material objects are for McTaggart unreal. He argued, for instance, in The Unreality of Time that it was not possible to produce a coherent account of a sequence of events in time, and that therefore time is an illusion. His book The Nature of Experience (1927) contained his arguments that space, time, and matter cannot possibly be real. In his Studies in Hegelian Cosmology, Cambridge, 1901, p. 196, he declared that metaphysics are not relevant to social and political action. McTaggart "... thought that Hegel was wrong in supposing that metaphysics could show that the state is more than a means to the good of the individuals who compose it. For McTaggart, "...philosophy can give us very little, if any guidance in action... . Why should a Hegelian citizen be surprised that his belief as to the organic nature of the Absolute does not help him in deciding how to vote? Would a Hegelian engineer be reasonable in expecting that his belief that all matter is spirit should help him in planning a bridge?
" The assertion that we can never be certain whether all of our putative outer experience is not mere imagining is idealism "
In the Postscript, Kierkegaard, as the pseudonymous philosopher Johannes Climacus, argues that a logical system is possible but an existential system is impossible. Hegel argues that once one has reached an ultimate understanding of the logical structure of the world, one has also reached an understanding of the logical structure of God's mind. Climacus claims Hegel's absolute idealism mistakenly blurs the distinction between existence and thought. Climacus also argues that our mortal nature places limits on our understanding of reality. As Climacus argues: "So-called systems have often been characterized and challenged in the assertion that they abrogate the distinction between good and evil, and destroy freedom. Perhaps one would express oneself quite as definitely, if one said that every such system fantastically dissipates the concept existence. ... Being an individual man is a thing that has been abolished, and every speculative philosopher confuses himself with humanity at large; whereby he becomes something infinitely great, and at the same time nothing at all."
A major concern of Hegel's Phenomenology of Spirit (1807) and of the philosophy of Spirit that he lays out in his Encyclopedia of the Philosophical Sciences (1817-1830) is the interrelation between individual humans, which he conceives in terms of "mutual recognition." However, what Climacus means by the aforementioned statement, is that Hegel, in the Philosophy of Right, believed the best solution was to surrender one's individuality to the customs of the State, identifying right and wrong in view of the prevailing bourgeois morality. Individual human will ought, at the State's highest level of development, to properly coincide with the will of the State. Climacus rejects Hegel's suppression of individuality by pointing out it is impossible to create a valid set of rules or system in any society which can adequately describe existence for any one individual. Submitting one's will to the State denies personal freedom, choice, and responsibility.
In addition, Hegel does believe we can know the structure of God's mind, or ultimate reality. Hegel agrees with Kierkegaard that both reality and humans are incomplete, inasmuch as we are in time, and reality develops through time. But the relation between time and eternity is outside time and this is the "logical structure" that Hegel thinks we can know. Kierkegaard disputes this assertion, because it eliminates the clear distinction between ontology and epistemology. Existence and thought are not identical and one cannot possibly think existence. Thought is always a form of abstraction, and thus not only is pure existence impossible to think, but all forms in existence are unthinkable; thought depends on language, which merely abstracts from experience, thus separating us from lived experience and the living essence of all beings. In addition, because we are finite beings, we cannot possibly know or understand anything that is universal or infinite such as God, so we cannot know God exists, since that which transcends time simultaneously transcends human understanding.
In his book Beyond Good and Evil, Part 1 On the Prejudice of Philosophers Section 11, he ridicules Kant for admiring himself because he had undertaken and (thought he) succeeded in tackling "the most difficult thing that could ever be undertaken on behalf of metaphysics."
Quoting Nietzsche's prose:
Moore proceeds by examining the Berkeleian aphorism esse est percipi: "to be is to be perceived". He examines in detail each of the three terms in the aphorism, finding that it must mean that the object and the subject are necessarily connected. So, he argues, for the idealist, "yellow" and "the sensation of yellow" are necessarily identical - to be yellow is necessarily to be experienced as yellow. But, in a move similar to the open question argument, it also seems clear that there is a difference between "yellow" and "the sensation of yellow". For Moore, the idealist is in error because "that esse is held to be percipi, solely because what is experienced is held to be identical with the experience of it".
Though far from a complete refutation. This was the first strong statement by analytic philosophy against its idealist predecessors--or at any rate against the type of idealism represented by Berkeley--this argument did not show that the GEM (in post Stove vernacular, see below) is logically invalid. Arguments advanced by Nietzsche (prior to Moore), Russell (just after Moore) & 80 years later Stove put a nail in the coffin for the "master" argument supporting (Berkeleyan) idealism.
Quoting Russell's prose (1912:42-43):
Whilst agreeing with (2), Searle argues that (1) is false, and points out that (3) does not follow from (1) and (2).
The second argument for (subjective) idealism runs as follows:
Searle goes on to point out that conclusion 2 simply does not follow from its precedents.
stock examples of use/mention confusions:
The distinction in philosophical circles is highlighted by putting quotations around the word when we want to refer only to the name and not the object.
stock examples of hyphenated entities:
Hyphenated entities are "warning signs" for conceptual idealism according to Musgrave because they over emphasise the epistemic (ways in which people come to learn about the world) activities and will more likely commit errors in use/mention. These entities do not exist (strictly speaking and are ersatz entities) but highlight the numerous ways in which people come to know the world.
In Sir Arthur Eddington's case use/mention confusions compounded his problem when he thought he was sitting at two different tables in his study (table-of-commonsense and table-of-physics). In fact Eddington was sitting at one table but had two different perspectives or ways of knowing about that one table.
Richard Rorty and Postmodernist Philosophy in general have been attacked by Musgrave for committing use/mention confusions. Musgrave argues that these confusions help proliferate GEM's in our thinking and serious thought should avoid GEM's.
While many religious philosophies are indeed specifically idealist, for example, some Hindu denominations view regarding the nature of Brahman, souls, and the world are idealistic, some have favored a form of substance dualism. Early Buddhism was not subjective idealistic. Some have misinterpreted the Yogācāra school of Mahayana Buddhism that developed the consciousness-only approach as a form of metaphysical idealism, but this is incorrect. Yogācāra thinkers did not focus on consciousness to assert it as ultimately real (Yogācāra claims consciousness is only conventionally real since it arises from moment to moment due to fluctuating causes and conditions), but rather because it is the cause of the karmic problem they are seeking to eliminate.
Some Christian theologians have held idealist views, substance dualism has been the more common view of Christian authors, especially with the strong influence of the philosophy of Aristotle among the Scholastics.
The theology of Christian Science includes a form of subjective idealism: it teaches that all that exists is God and God's ideas; that the world as it appears to the senses is a distortion of the underlying spiritual reality.
A Course in Miracles, a spiritual self-study course published in 1976, represents an explicitly idealist, pure nondualistic thought system. In the Course, only God and His Creation, which is Spirit and has nothing to do with the world, are real. The physical universe is an illusion and does not exist. The Course compares the world of perception with a dream. It arises from the projection of the dreamer, i.e. the mind ("projection makes perception," T-21.in.1:5), according to its wishes (perception "is the outward picture of a wish; an image that you wanted to be true," T-24.VII.8:10). The purpose of the perceptual world is to ensure our separate, individual existence apart from God but avoid the responsibility and project the guilt onto others. As we learn to give the world another purpose and recognize our perceptual errors, we also learn to look past them or "forgive," as a way to awaken gradually from the dream and finally remember our true Identity in God. The Course’s nondualistic metaphysics is similar to Advaita Vedanta. However, A Course in Miracles differs in that it adds a "motivation" for the illusory existence of the perceptual world (for a further discussion, see Wapnick, Kenneth: The Message of A Course in Miracles, 1997, ISBN 0-933291-25-6).
The word "ideal" is commonly used as an adjective to designate qualities of perfection, desirability, and excellence. This is foreign to the epistemological use of the word "idealism" which pertains to internal mental representations. These internal ideas represent objects that are assumed to exist outside of the mind.