反之 vs 相反 (fǎn zhī vs xiāng fǎn): logical converse or direct opposite
反之 and 相反 both correspond to 'on the contrary' in English, but they differ in usage: 反之 is a formal logical connector meaning 'conversely' or 'if not, then...', used to introduce the opposite of a condition; 相反 is an adjective or adverb meaning 'contrary' or 'opposite', stating a factual opposition between two statements. Choosing the wrong one can create logical or register errors.
The key distinction between 反之 and 相反 lies in their function and formality. 反之 is a formal conjunction used to present the logical converse of a preceding statement, often in condition-contrast structures meaning 'otherwise' or 'conversely'. 相反, on the other hand, is a stative adjective or adverb that directly asserts that two things are opposite, often used as a predicate ('is the opposite') or as a connective meaning 'on the contrary'. While 相反 can appear in both formal and informal writing, 反之 is primarily found in academic or official texts. Understanding this difference helps avoid logical mismatches in Chinese writing.
When to use each
Use 反之 to introduce the logical converse of a condition or statement, especially in formal writing. It often follows a hypothetical or conditional clause and implies 'if not... then...'. For example: '如果...[then]...; 反之，...' (if A, then B; conversely, if not A, then not B). It is common in academic, legal, and philosophical contexts.
反之 is rarely used in spoken Chinese; it carries a high formal register and is typically found in written discourse where logical flow is emphasized.
Use 相反 to assert a direct opposition between two facts, opinions, or situations. It can function as a predicate (e.g. '情况相反' the situation is the opposite) or as an adverbial connector at the start of a clause (e.g. '相反，他认为...' on the contrary, he thinks...). It is common in both formal and informal contexts.
相反 can be preceded by '恰恰' or '正好' for emphasis: '恰恰相反' means 'quite the opposite'.
At a glance
| 反之 | 相反 | |
|---|---|---|
| Main function | Introduces logical converse of a condition | States direct factual opposition |
| Formality | High; formal written only | Neutral; both formal and informal |
| Typical position in sentence | Conjunction between clauses, often after a semicolon | Predicate after '是', or adverb at clause start |
| Can it be a predicate? | No | Yes, with '是' or alone |
| Negation | Not directly negatable | Can be negated as '不相反' (rare), usually '并不相反' |
Examples
- 反之只有提高效率，才能降低成本；反之，效率低下则成本上升。Zhǐyǒu tígāo xiàolǜ, cáinéng jiàngdī chéngběn; fǎn zhī, xiàolǜ dīxià zé chéngběn shàngshēng.Only by improving efficiency can we reduce costs; conversely, low efficiency leads to higher costs.反之 introduces the logical converse of the preceding condition.
- 相反他表面上很冷静，相反，内心其实很紧张。Tā biǎomiàn shàng hěn lěngjìng, xiāngfǎn, nèixīn qíshí hěn jǐnzhāng.He appears calm on the surface; on the contrary, he is actually very nervous inside.相反 states a direct factual opposition between appearance and reality.
- 相反你的观点和我的完全相反。Nǐ de guāndiǎn hé wǒ de wánquán xiāngfǎn.Your opinion is completely opposite to mine.相反 used as a predicate adjective.
- 反之经济发展依赖于科技创新；反之，科技创新也需要经济支持。Jīngjì fāzhǎn yīlài yú kējì chuàngxīn; fǎn zhī, kējì chuàngxīn yě xūyào jīngjì zhīchí.Economic development depends on technological innovation; conversely, technological innovation also requires economic support.反之 shows mutual conditionality in a formal context.
- 相反她不同意我的意见，相反，她支持我的想法。Tā bù tóngyì wǒ de yìjiàn, xiāngfǎn, tā zhīchí wǒ de xiǎngfǎ.She does not agree with my opinion; on the contrary, she supports my idea.✗ If 反之 were used here it would be wrong because there is no conditional relationship, only direct opposition.
Common mistakes
- Using 反之 to simply mean 'on the contrary' when stating factual opposition (use 相反).
- Using 相反 as a formal logical connector meaning 'conversely' in conditional arguments (incorrect; 相反 states fact, not condition).
- Treating 反之 as suitable for spoken conversation; it is too formal and may sound unnatural.
- Omitting the contrastive clause after 反之; it must link back to a preceding condition.
FAQ
- When do I use 反之 vs 相反?
- Use 反之 as a formal logical connector meaning 'conversely/otherwise' in conditional arguments; use 相反 to state a direct factual opposition, whether as a predicate or clause connector.
- Can 相反 be used at the beginning of a sentence?
- Yes, 相反 can start a sentence as an adverbial meaning 'on the contrary', e.g. '相反，我不相信他' (On the contrary, I don't believe him).
- Is 反之 common in everyday Chinese?
- No, 反之 is quite formal and appears mostly in written academic or official language. In speech, 相反 or other expressions like '否则' are preferred.
- What is the difference in grammar between 反之 and 相反?
- 反之 is a conjunction that connects clauses, usually in a 'if...then; conversely...' pattern. 相反 is an adjective or adverb; it can be used as a predicate with '是' or as a connective without verb inflection.