解釋為什麼的一套想法
核心：用來解釋現象的一套想法，不論是嚴謹的學說，還是個人的猜測。
unproven explanation · noun · B2
An idea or set of ideas that tries to explain why something happens, especially one not yet fully proved.
理論 / 學說
核心畫面
You can picture a theory as: a 'way of seeing' that someone builds in their head to explain why something happens — a frame of ideas placed over the messy world to make sense of it. It lives in the realm of thinking, not yet in the realm of proof or of actually doing — and that gap between 'on paper' and 'in real life' is where the other meanings grow.
可以想成：有人在腦中搭起一套「看事情的方式」，用來解釋某件事為什麼會這樣——像一個用想法做成的框，罩在亂糟糟的世界上…更多收起
可以想成：有人在腦中搭起一套「看事情的方式」，用來解釋某件事為什麼會這樣——像一個用想法做成的框，罩在亂糟糟的世界上，讓它變得說得通。它活在「想」的層次，還沒落到「證明了」或「真的去做」的層次——而「紙上談」跟「實際做」之間的那道縫，正是其他意思長出來的地方。Three branches
一門學科的道理部分
把「想的層次」整理成一門學問裡的「道理、規則」那一塊，跟「實作」那一塊相對。
theory (academic subject) · noun · B2
The general ideas and rules of a subject, rather than the practical part of doing it.
理論（學科）
理論上（但實際未必）
直接點出「想的層次 vs 真實世界」那道縫：照道理該如此，但實際也許不然。
in theory · noun · B2
Used in the phrase 'in theory' to say something should be true or happen, but maybe will not in real life.
理論上
原始詞典資料8 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
theorynoun/ˈθɪə.ɹi/
- 1
A description of an event or system that is considered to be accurate.
- As they encrease the hatred of vice in some, so doe they enlarge the theory of wickednesse in all.
- 2
sciencesA coherent statement or set of ideas that explains observed facts or phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed; a hypothesis confirmed by observation, experiment etc.
- In its most proper acceptation, theory means the completed result of philosophical induction from experience.
- Does this mean, then, that there can be no such thing as a theory of literature?
- 3
The underlying principles or methods of a given technical skill, art etc., as opposed to its practice.
- Lopukhov wrote a number of books and articles on ballet theory, as well as his memoirs.
- 4
mathematicssciencesA field of study attempting to exhaustively describe a particular class of constructs.
- Knot theory classifies the mappings of a circle into 3-space.
- It's just a theory I have, and I wonder if women would agree. But don't men say a lot about themselves when a short-skirted woman slides out of a car or chair?
- 5
human-scienceslogicmathematicsA set of axioms together with all statements derivable from them; or, a set of statements which are deductively closed. Equivalently, a formal language plus a set of axioms (from which can then be derived theorems). The statements may be required to all be bound (i.e., to have no free variables).
- A theory is consistent if it has a model.
- 6
The standardization and study of fixed sequences of moves, especially in the opening phase of a game.
- Near-synonym: joseki
- 7
obsoleteMental conception; reflection, consideration.
- 8
informalA hypothesis or conjecture.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。