「不排除有此可能」是等如「有此可能」嗎？
「沒有證據有效」是等如「沒有效」嗎？
「看不到證據」是等如「沒有證據」嗎？
有人認為：「不排除有此可能」的意思是，沒有證據顯示這種事情可能發生，也沒有證據顯示這種事情不可能發生；也就是說，事情是否可能發生，我們都不知道，根本完全沒有指出任何因果關係。
有人認為：當人說「沒有證據顯示···」時，我們要問「在甚麼情況下沒有證據？」
有人認為：
| Level | Legal standards of proof | Informal scientific levels of certainty | Bayesian probability | Level in IPCC |
|---|---|---|---|---|
| 10 | Beyond any doubt | Fundamental theory that explains a wide range of observation | 100% | (absent) |
| 9 | Beyond a reasonable doubt | Rigorously proven, critical experiment(s) give(s) a clear result | > 99% | Virtually certain |
| 8 | Clear and convincing evidence | Substantially proven; a few details remain to be worked out; reasonably certain | 90 - 99% | Very likely |
| 7 | Clearly showing | Very probable | 80 - 90% | Likely |
| 6 | Substantial and credible evidence | Probable; evidence points in this direction, but not fully proven | 67 - 80% | Likely |
| 5 | Preponderance of evidence | If I have to choose, this seems more likely true than untrue | 50 - 67% | Medium likelihood |
| 4 | Clear indication | Attractive but unproven; evidence is beginning to accumulate in this direction | 33 - 50% | Medium likelihood |
| 3 | Probable cause: reasonable grounds for belief | Plausible hypothesis, supported by some evidence | 10- 33% | Unlikely |
| 2 | Reasonable, articulate grounds for suspicion | Possible | 1 - 10% | Very unlikely |
| 1 | No reasonable grounds for suspicion | Unlikely: available evidence is against it, or violates existing paradigms, but not entirely ruled out | < 1% | Exceptionally unlikely |
| 0 | Impossible | Against the known laws of physics or other science | 0% | Exceptionally unlikely |
IPCC 是 Second Report of the Inter-Governmental Panel on Climate Change.
參考：Charles West 的 “Expressing Scientific Uncertainty” 在 “Law, Probability and Risk” 的 2003 年版的第 2 期，第 25 至 46 頁。
你有鄉音嗎？你聽得懂別人的鄉音嗎？你用別人的鄉音嗎？