Imagine two scenarios:

1) I distrust Bob because he has betrayed me in the past. Bob tells me that "rojo" is the Spanish word for red. I don't trust Bob, so I go and look up "rojo" in a Spanish-English dictionary.

2) I trust Sue because on more than one occasion she came through for me when she said she would. She tells me that "Azul" is the Spanish word for blue. I am not confident in my Spanish, so I look it up in a Spanish-English dictionary.

Maybe the answer here is that the end of looking it up does not justify the reasoning behind getting the dictionary. However, I think it can be argued that if you really trusted Sue, you would not look it up.

  • 4
    The natural meaning of the term is 'even if you trust someone, you should verify what they say', or 'trust people who are trustworhy, but realize they are fallible'. So no, it's not self-contradictory – Canadian Coder Sep 20 '17 at 19:17
  • There is a tension between trusting and verifying, but it is a pragmatic motto. Often, we do not have the luxury of time to verify somebody's claims before we have to act on them, or it is too costly to be worth the effort, we have to either trust the person or not. In the aftermath, or if it is not too costly, it does not hurt to verify their claims to decide if they shall remain worthy of our trust in the future. – Conifold Sep 20 '17 at 20:05
  • I would say "trust but verify" is suggested as a default position. In other words, if you have no information about the person or the statement, "trust but verify" what they say. I don't think the phrase is meant to apply when you know something about the person and/or the statement being made. – barrycarter Sep 21 '17 at 16:55
  • But my question, asked a more direct way, is: if you are going to double check them in both situations, are you really trusting at all? The result is the same and the concept of trust seems to be very intangible and nebulous. – J. Tate Sep 22 '17 at 11:20
  • 'Trust' seems to do no work here, to guide no behaviour, if I check the word borh of Bob, whom I distrust, and Sue, whom I trust. The cognitive reliance I place on both is equal - nil. I only trust the dictionary. – Geoffrey Thomas Nov 25 '17 at 13:07

The context may seem to allow other possubilities. I can see a context where the person seems to equate trust with honor or respect. So if i take this inThe argument if you honor or respect me you would not need to verify. This is a context taken by nearly all military supervisors. You will not say to a commissioned officer " let me verify that your information is correct sir". The officer tells you to act you must act without verification . So not following the order seems to attack the honor or respect you have for that supervisor. This seems to be what the sample above touches on. Respect me and do not question me. If you respect me you would not question me. This is what i see as the hidden message. I also see you are more concerned with result than the person so you miss the context. Would you tell a four star general that you will have to veriy that? Most service members would not even in the case the General is completely wong. This is simply being practical over being conceptual. Do you not see questioning a general officer's claim as being inappropriate? Any enlisted service member would know better. There is a reason it rarely happens. Even if you were ignorant for sure you will be pulled aside and briefed never ever to do that again. The you still have to be punished! So propositional logic does not give you tacit premises. Perhaps this is why you see the case differently.


The phrase as stated is contradictory. However, as "commonly" understood, it means to "not trust blindly" because humans are fallible and unpredictable. In other words, don't trust 100%.
The "degree of trust" varies depending on the "reputation" of the person making the statement. For example, Sue might get a rating of 80%, while Bob might get a rating of 40%. If this is the case, you would be justified in trusting Sue more than Bob, but if you need 100% certainty, you have to verify.


There's a difference between trusting someone and knowing something to be true. So no, it is not contradictory.

First of all, Sue could be wrong even if she told you something in good faith and believed it to be true. The meaning of trust is not that you trust somebody to be infallible, it means you trust them to be well-intentioned and undeceitful.

Secondly, if you were to later on converse with another person, then that person may not trust Sue at all. Hence, by knowing something to be true for yourself, it will benefit you in later instances where you need to provide a convincing argument for why something is true, and where "because Sue told me" may not suffice.


The phrases are not self-contraditory, but they do call for one to think about the definitions of these words and what options are available.

One interpretation which I find very powerful is to trust the individual on the short run, but in the long run, verify what they say.

One can use Baysean inference to phrase that in a more formal way. When one hears a statement such as "'Rojo' is the Spanish word for 'red,'" one may assign it a prior which gives it a non-zero probability of being true, simply because Bob said as such. You can give some level of trust to Bob. However, as this statement becomes more important, you should seek additional input which can be used to increase the probability of it being true to a value closer to 100%.

If I'm talking to an average Spanish speaker, I may trust Bob's statement. At worst, I make a fool out of myself. However, if I am about to make a speech to a large number of Spanish speakers, and the success or failure of my platform depends on the quality of my speaking, I should seek to verify.

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