Idealism: Past, Present, and Future

Idealism is a prominent tradition in the history of philosophy, both Western and Eastern. It can be defined by acceptance of the premise that the universe is first and foremost a manifestation of mind or reason, rather than of dead, mindless matter. Instead of seeing mind/reason as relatively late products of unintelligent, mechanical processes in physical nature, as Materialism holds, Idealism by and large turns this developmental sequence around and sees mind/reason as the 'motor' behind physical processes towards increasing complexity.

A SHORT OVERVIEW OF THE IDEALIST TRADITION
Idealism has ancient roots in both Western and Eastern philosophy. In Eastern philosophy, Idealist themes can be found in the Indian philosophies of the Vedanta and Yogacara Buddhism. Vedanta is the more ancient of these: it conceives of the ultimate ground of reality or "Brahman" as pure "self-luminous" consciousness. Continuing Vedantic themes in a Buddhist setting, Yogacara Buddhism claims that only "pure mind" is ultimately real. In Eastern philosophy, however, Idealism often goes hand in hand with mystical acosmism, where the full reality of the empirical world is denied in contrast to the mystical state of pure, contentless consciousness reached in meditation. This happens paradigmatically in the non-dual Vedanta of the 8th century Indian philosopher Shankara.

For a more positive evaluation of the empirical world from an Idealist perspective we must turn to Idealism in the Western tradition. This is not to say, however, that Eastern Idealism has no value. Moreover, some Idealists of the Western tradition (Parmenides, Schelling, Bradley) have come awfully close to the mystical acosmism of their Eastern counterparts.

In Western philosophy the tradition of Idealism arguably started with the Presocratic philosophers Anaxagoras ("it is intelligence that arranges and causes all things") and Parmenides ("thinking and being are the same"). They passed the torch to Plato, who famously saw the empirical world as an image or expression of eternal Ideas. Plato in turn bequeathed the Idealist vision of the universe to Plotinus, who added to Platonism the Aristotelian conception of God as "thought thinking itself", thereby arriving at a picture of the universe as the "emanation" of the One's self-contemplation. In this way Plotinus effectively anticipated the Absolute Idealism of the post-Kantian German Idealists Schelling and Hegel.

But before the latter could arrive on the scene, modern philosophy first had to take the epistemological turn, notably through Descartes' focus on individual self-consciousness as the paradigm of certain knowledge. From Descartes onwards, Idealism took on a subjective flavor, centering on the epistemological argument that our knowledge of reality is confined to our own thoughts and perceptions (Berkeley, Kant).

The post-Kantian German Idealists, although starting from this epistemologically inspired Idealism, arguably returned to Idealism's more ontological beginnings in Greek philosophy, combining the Cartesian focus on the cogito as the paradigm of certain knowledge ("Absolute Knowledge") with the more Neoplatonist focus on "thought thinking itself" as the teleological origin of the empirical universe.

In the second half of the 19th century, the legacy of German Absolute Idealism was taken up and further developed by the British Idealists (Green, Bradley, McTaggart, Bosanquet, Collingwood, Whitehead e.a.) and the American Idealists, most notably Royce. On the European Continent the tradition of Idealism was continued by Husserl.These philosophers took Idealism into the 20th century, enriching it with themes from contemporary logic, mathematics, and natural science. In the beginning of the 20th century, however, British and American Idealism were all but effaced by the emergence of logical empiricism and analytic philosophy. The original proponents of the latter, notably Moore and Russell, asserted their own position through vigorous opposition to and ridicule of their Idealist predecessors, resulting in a distorted caricature of what Idealism really amounts to.

In present times, however, this caricature is in the process of being corrected, and Idealism is experiencing a revival owing to new developments in philosophy and science. Four must be singled out for special attention:

(1) The so-termed "hard problem of consciousness" and the influence of Russellian monism: Conscious states or "qualia" appear to be irreducible to physics and even to be the sole candidates for being the intrinsic entities on which physical structure rests, thereby suggesting a panpsychist ontology (e.g. Galen Strawson).

(2) The emergence of Normative Idealism in opposition to physicalist Eliminativism: Philosophers like McDowell and Brandom have made a remarkable return to Kant and Hegel by pointing out that conceptuality and rationality in general are intrinsically normative, having to do with how people ought to think rather than with how they factually think. Thus, given the conceptually laden impact of empirical experience on thought, the empirical world must have a normative significance that cannot be accounted for in strictly naturalistic or scientistic terms. According to philosophers like McDowell and Brandom, the empirical world turns out to have a normative-conceptual structure that is best approached by returning to the Idealisms expounded by Kant and Hegel.

(3) The focus on "observer participancy" in contemporary physics: The role of conscious observation in quantum mechanics and the apparent fine-tuning of the universe for the evolution of intelligent life (i.e. the anthropic principle) have, together with the hard problem of consciousness, suggested to some physicists (e.g. Von Neumann, Wigner, Wheeler) that consciousness plays a more fundamental role in the universe than physical science has traditionally assumed. In this way physics could lead to a scientific reanimation of Idealism.

(4) The rediscovery of (Neo-)Platonic Idealism in relation to Leibniz's question: There is at present a remarkable revival of interesting in Leibniz's famous question, "Why is there something rather than nothing?". Various philosophers and physicists have rebegun to develop possible solutions to this most fundamental problem. In this context the ontological importance of (Neo-)Platonic Idealism has been rediscovered by philosphers like Leslie and Rescher. Agreeing with other philosophers, such as Nozick, that the ultimate cause or ground of existence must also be self-causing or self-grounding (in order to avoid a regress), Leslie and Rescher argue that the self-explaining principle underlying existence is best conceived in terms of value, analogous to Plato's and Plotinus' focus on the "Good beyond Being". Value, as Leslie and Rescher point out, explains existence, because it is good that there is existence, and at the same time value explains itself as well, because it is good that there is goodness. In this way the (Neo-)Platonic focus on the Good as the self-grounding of ground of existence has made a remarkable return in contemporary philosophy. What is lacking, however, in both Leslie and Rescher is a proper acknowledgement of the role played by absolute self-awareness in this ontological self-grounding. In this regard they lag behind Plotinus who not only conceived of the One as the "Good beyond Being" but also as absolute self-awareness, such that "its being is its act of looking at itself" as Plotinus writes. Since, as remarked, Plotinus in this regard anticipated the Absolute Idealism of Schelling and Hegel, the introduction of the latter into the current debate about Leibniz's question remains one of the desiderata of future research in Idealism.

VARIETIES OF IDEALISM
As the above history of Idealism makes clear, albeit in a very truncated fashion, Idealism is by no means a single school or system of thought. Besides the dispute between Idealism and Materialism or Physicalism, there is also the internal dispute between rival schools of Idealism. Something of this disagreement already appeared above when it was said that "Idealism can be defined by acceptance of the premise that the universe is first and foremost a manifestation of mind or reason". The disjunction -- mind or reason -- signals a disagreement among Idealists concerning the nature of that ultimate ground underlying the empirical world. Is that ground a mind in a subjective sense, as in (self-)consciousness or selfhood? Or should we rather banish subjectivity from the Idealist explanation of the world, focusing rather on an impersonal and objective reason ("logos") as the ultimate ground or reality? Given this disjunction, Idealist philosophy forms a gradient spectrum between the extremes of subjectivism and objectivism. Roughly the following positions can be distinguished:

(1) Objective Idealism: Empirical reality is the manifestation of objective, non-personal and non-spatiotemporal ideal entities, such as Plato's Ideas, or mathematical structures as in Mathematical Platonism. The latter is currently advocated by physicists like Penrose and Tegmark. Normative Idealism (McDowell, Brandom), with its focus on the constitutive importance of publicly valid conceptual norms, also seems to be a species of Objective Idealism.

(2) Subjective Idealism: Empirical reality exists only for a conscious subject who constructs it on the basis of its experiences and a priori cognitive structures. We can know nothing about reality as it exists apart from the knowing subject. In its phenomenalist version, this position was advocated by Berkeley. In a more rationalist vein the position was advocated by Kant and Fichte.

(3) Absolute Idealism: There is nothing apart from the absolute Self or Spirit that unfolds itself in the empirical world. In a sense Absolute Idealism combines Objective and Subjective Idealism in that it conceives of the ultimate ground of reality as an ideal Self or Spirit whose self-realization involves the Ideas highlighted in Platonism. This position has been famously advocated by Schelling and Hegel, though in important ways they were already anticipated by Plotinus and later Neoplatonists (e.g. Proclus, Eriugena).

(4) Panpsychist Idealism: This is the view that consciousness, mind or soul is a universal feature of all things. It doesn't necessarily say that all physical objects are manifestations of mind but it does say that all physical objects have mind or at least an aspect of mentality. Panpsychism may go hand in hand with metaphysical pluralism, stating that the universe is a collection of countless many minds. Famous Panpsychists are Thales, Spinoza, Leibniz, James, and most recently Galen Strawson. Panpsychism is in itself a very diverse doctrine, and its relation to the other forms of Idealism has up till now not been properly dealt with. This is one of the desiderata of future research.