physics

Subjective idealism

Subjective idealism is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Subjective idealism rather than just read about it. In short: Subjective idealism, or empirical idealism or immaterialism, is a form of ontological monism that holds that only minds and mental contents exist. It entails and is generally identified or associated with immaterialism, the doctrine that material things do not exist.

Key takeaways

Subjective idealism belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Subjective idealism to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Subjective idealism from memory before moving on to harder problems.

Reference excerpt

Subjective idealism, or empirical idealism or immaterialism, is a form of ontological monism that holds that only minds and mental contents exist. It entails and is generally identified or associated with immaterialism, the doctrine that material things do not exist. Subjective idealism rejects dualism, neutral monism, and materialism; it is the contrary of eliminative materialism, the doctrine that all or some classes of mental phenomena (such as emotions, beliefs, or desires) do not exist, but are sheer illusions.

Overview Subjective idealism is a fusion of phenomenalism or empiricism, which confers special status upon the immediately perceived, with idealism, which confers special status upon the mental. Idealism denies the knowability or existence of the non-mental, while phenomenalism serves to restrict the mental to the empirical. Subjective idealism thus identifies its mental reality with the world of ordinary experience, and does not comment on whether this reality is "divine" in some way as pantheism does, nor comment on whether this reality is a fundamentally unified whole as does absolute idealism. This form of idealism is "subjective" not because it denies that there is an objective reality, but because it asserts that this reality is completely dependent upon the minds of the subjects that perceive it. The earliest thinkers identifiable as subjective idealists were certain members of the Yogācāra school of Indian Buddhism, who reduced the world of experience to a stream of subjective perceptions. Subjective idealism made its mark in Europe in the 18th-century writings of George Berkeley, who argued that the idea of mind-independent reality is incoherent, concluding that the world consists of the minds of humans and of God. Subsequent writers have continuously grappled with Berkeley's skeptical arguments. Immanuel Kant responded by rejecting Berkeley's immaterialism and replacing it with transcendental idealism, which views the mind-independent world as existent but incognizable in itself. Since Kant, true immaterialism has remained a rarity, but is survived by partly overlapping movements such as phenomenalism, subjectivism, and perspectivism. Hegel rejected Kant's immaterialism, demeaning it to a "reduction of the facts of consciousness to a purely personal world."

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Subjective idealism

Start with the simplest possible case. Write down what Subjective idealism claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Subjective idealism before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Subjective idealism ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Subjective idealism

In research: Subjective idealism appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Subjective idealism in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Subjective idealism is common in secondary-school and first-year university syllabi. It links to neighbouring topics George Berkeley, Idealism, Metaphysics of mind, so understanding it makes those chapters shorter.
In everyday life: Look for Subjective idealism outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Subjective idealism in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Subjective idealism means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Subjective idealism out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Subjective idealism in simple terms?

Why does Subjective idealism matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Subjective idealism?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Subjective idealism.