History of Idealism

Bronze Sculpture Of Plato
Bronze Sculpture Of Plato. Buyenlarge / Contributor/Archive Photos/Getty Images

Idealism is the category of philosophical systems that claim reality is dependent upon the mind rather than independent of the mind. Or, put another way, that the ideas and thoughts of a mind or minds constitute the essence or fundamental nature of all reality.

Extreme versions of Idealism deny that any 'world' exists outside of our minds. Narrower versions of Idealism claim that our understanding of reality reflects the workings of our mind first and foremost - that the properties of objects have no standing independent of the minds perceiving them.

If there is an external world, we cannot truly know it or know anything about it; all we can know are the mental constructs created by our minds, which we then (falsely, if understandably) attribute to an external world.

Theistic forms of idealism limit reality to the mind of God.

Important Books on Idealism

The World and the Individual, by Josiah Royce
Principles of Human Knowledge, by George Berkeley
Phenomenology of Spirit, by G.W.F. Hegel
Critique of Pure Reason, by Immanuel Kant

Important Philosophers of Idealism

Gottfried Wilhelm Leibniz
Georg Wilhelm Friedrich Hegel
Immanuel Kant
George Berkeley
Josiah Royce

What is the "Mind" in Idealism?

The nature and identity of the "mind" upon which reality is dependent is one issue that has divided idealists of various sorts. Some argue that there is some objective mind outside of nature, some argue that it is simply the common power of reason or rationality, some argue that it is the collective mental faculties of society, and some focus simply on the minds of individual human beings.

Platonic Idealism

According to Platonic Idealism, there exists a perfect realm of Form and Ideas and our world merely contains shadows of that realm. This is often called "Platonic Realism" because Plato seems to have attributed to these Forms an existence independent of any minds. Some have argued, though, that Plato nevertheless also held to a position similar to Kant's Transcendental Idealism.

Epistemological Idealism

According to René Descartes, the only thing that can be known is whatever is going on in our minds - nothing of an external world can be directly accessed or known about. Thus the only true knowledge we can have is that of our own existence, a position summed up in his famous statement "I think, therefore I am." He believed that this was the only knowledge claim which could not be doubted or questioned.

Subjective Idealism

According to Subjective Idealism, only ideas can be known or have any reality (this is also known as solipsism or Dogmatic Idealism). Thus no claims about anything outside of one's mind have any justification. Bishop George Berkeley was the main advocate of this position, and he argued that so-called "objects" only had existence insofar as we perceived them - they were not constructed of independently-existing matter. Reality only seemed to persist either because of people continuing to perceive objects or because of the continuing will and mind of God.

Objective Idealism

According to this theory, all of reality is based on the perception of a single Mind - usually, but not always, identified with God - which then communicates its perception to the minds of everyone else.

There is no time, space, or other reality outside of the perception of this one Mind; indeed, even we humans are not truly separate from it. We are more akin to cells that are part of a larger organism rather than independent beings. Objective Idealism started with Friedrich Schelling, but found supporters in G.W.F. Hegel, Josiah Royce, and C.S. Peirce.

Transcendental Idealism

According to Transcendental Idealism, developed by Kant, this theory argues that all knowledge originates in perceived phenomena which have been organized by categories. This is also sometimes known as Critical Idealism and it does not deny that external objects or an external reality exists, it just denies that we do not have access to the true, essential nature of reality or objects. All we have is our perception of them.

Absolute Idealism

According to Absolute Idealism, all objects are identical with some idea and the ideal knowledge is itself the system of ideas. It is also known as Objective Idealism and is the sort of idealism promoted by Hegel. Unlike the other forms of idealism, this is monistic - there is only one mind in which reality is created.