应该 vs 可能 (yīnggāi vs kěnéng): epistemic 'should' vs 'maybe'
Both 应该 (yīnggāi) and 可能 (kěnéng) can express epistemic uncertainty, but they convey different levels of certainty. 应该 indicates a strong probability based on logic or evidence (like “should” in English), while 可能 denotes mere possibility (like “maybe” or “might”). 应该 also has a deontic use (obligation), whereas 可能 does not.
In Chinese, both 应该 (yīnggāi) and 可能 (kěnéng) are used to express uncertainty about a situation, but they differ in strength. 应该 conveys a high degree of probability based on reasoning, evidence, or expectation—similar to 'should' or 'must be' in English. 可能 indicates that something is possible but not necessarily likely—like 'maybe' or 'might'. Additionally, 应该 can also express obligation ('should do'), while 可能 has no such deontic use. Choosing the right word depends on how confident the speaker is and whether they are inferring from evidence or simply speculating.
When to use each
Use 应该 when you have a strong expectation based on logic, evidence, or common sense. It suggests the speaker believes something is very likely true. For example: 他应该到了 means 'He should have arrived' (I infer from the time). 应该 also expresses obligation ('should do'), e.g., 你应该早睡 'You should go to bed early'.
In epistemic uses, 应该 is still a guess, but it implies the speaker can justify the guess with reasoning. It is weaker than 肯定 (definitely) but stronger than 可能.
Use 可能 to express that something is plausible or uncertain—that it 'may' or 'might' happen. It conveys a lower degree of certainty than 应该. For example: 明天可能下雨 'It might rain tomorrow'. 可能 can also be a noun meaning 'possibility', e.g., 没有可能 'There is no possibility'.
可能 does not carry a sense of logical expectation; it simply indicates that something is within the realm of possibility. It is neutral about the speaker's evidence.
At a glance
| 应该 | 可能 | |
|---|---|---|
| Degree of certainty | Strong probability (logically expected) | Weak possibility (uncertain) |
| Type of usage | Epistemic (inference) + Deontic (obligation) | Primarily epistemic (possibility) |
| Negation | 不应该 = 'should not' (not obligated / unlikely) | 不可能 = 'impossible' |
| Typical English equivalent (epistemic) | should, must be | maybe, might, possibly |
Examples
- 应该他应该已经到公司了。Tā yīnggāi yǐjīng dào gōngsī le.He should have arrived at the office by now.Inference based on time and routine.
- 可能他可能还没起床。Tā kěnéng hái méi qǐchuáng.He might not have gotten up yet.Speculation without strong evidence.
- 应该这道题应该很简单。Zhè dào tí yīnggāi hěn jiǎndān.This problem should be very simple.Expectation based on judgment.
- 可能明天可能下雨。Míngtiān kěnéng xià yǔ.It might rain tomorrow.Weather forecast with uncertainty.
- 应该他不应该这么晚回家。Tā bù yīnggāi zhème wǎn huí jiā.He shouldn't come home so late.Deontic obligation (negative).
- 可能那件衣服可能太贵了。Nà jiàn yīfu kěnéng tài guì le.That dress might be too expensive.Subjective guess.
Common mistakes
- Using 可能 when making a logical inference based on clear evidence (e.g., 'He is usually on time, so he should be here' – use 应该).
- Using 应该 to express a pure guess with no reasoning (e.g., 'Maybe he is sick' – use 可能).
- Mistaking 不应该 to mean 'impossible' – 不应该 means 'should not' (obligation), 不可能 means 'impossible'.
- Using 可能 to express obligation (e.g., 'You should study' – cannot use 可能; use 应该).
FAQ
- When do I use 应该 vs 可能 for epistemic meaning?
- Use 应该 when you have a reason to believe something is true (strong expectation), e.g., 他应该在家 (He should be at home, because it's late). Use 可能 when you are less sure, e.g., 他可能在家 (He might be at home, I'm not sure).
- Can 应该 ever mean 'maybe'?
- In casual speech, 应该 sometimes weakens to a softer guess, but it still implies higher probability than 可能. Strictly speaking, 应该 carries a sense of expectation, while 可能 is neutral possibility.
- What's the difference between 不应该 and 不可能?
- 不应该 means 'should not' (either not obligated or not expected to be true based on reasoning), e.g., 他不应该迟到 (He should not be late). 不可能 means 'impossible', e.g., 他不可能迟到 (It's impossible that he is late).
- Can 可能 be used for ability like 会 or 可以?
- No. 可能 does not express personal ability. For ability, use 会 (learned skill) or 能 (capability). 可能 only expresses possibility or likelihood.