science

Trialism

Trialism is a science 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 Trialism rather than just read about it. In short: Trialism in philosophy was introduced by John Cottingham as an alternative interpretation of the mind–body dualism of Descartes. Trialism keeps the two substances of mind and body, but introduces a third substance, sensation, belonging to the union of mind and body.

Key takeaways

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

Reference excerpt

Trialism in philosophy was introduced by John Cottingham as an alternative interpretation of the mind–body dualism of Descartes. Trialism keeps the two substances of mind and body, but introduces a third substance, sensation, belonging to the union of mind and body. This allows animals, which do not think like humans, to be regarded as having sensations and not as being mere automata.

Background Cottingham introduced this term after noting that Descartes' account of sensation and imagination has placed his official dualism under considerable pressure: "Partly as a result of this, we often see the emergence, in Descartes’ writings on human psychology, of a grouping of not two but three notions – not a dualism but what may be called a ‘trialism’." According to Cottingham, Descartes added the third notion of sensation "alongside thought and extension without proceeding to reify it as a separate substance". Thinkers such as Daniel Garber and Tad Schmaltz supported this by citing a letter in the correspondence between Descartes and Princess Elizabeth of Bohemia, which indicated that he changed his mind from a dualistic view.

References

Sources Cottingham, J. Cartesian Trialism, Mind, 1985.

Worked examples

Example 1 — a first encounter with Trialism

Start with the simplest possible case. Write down what Trialism claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Trialism 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 Trialism 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 Trialism

In research: Trialism appears in science 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 Trialism 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: Trialism is common in secondary-school and first-year university syllabi. It links to neighbouring topics Christianity studies stubs, Dualism (philosophy of mind), Religious philosophy stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Trialism 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 Trialism in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Trialism 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 Trialism out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Trialism in simple terms?

Why does Trialism matter?

Because it connects several science 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 Trialism?

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 Trialism.