It's something most of us have heard many times, and would have a general concept for, but when pressed ... just what does it mean? Is it an oxymoron, or not?
What are the origins of this phrase?
Some links via google:
My six year old summed it up tonight... Me: "Did you brush your teeth?" Him: "Yes" "Are you SUuuure?" "Yes" "Should I check your teeth and toothbrush." "Yes" "Why do you want me to check." "So you know I did it."
The point is, six year olds know inherently, without being able quite to rationalize it, what the concept involves.
Teenagers on the other hand, apply some logic which we, if we remain on the surface of the issue, can't really disagree with very well. "I check up on you honey, 'cause I'm supposed to as a good parent." "If you REALLY trusted me, Dad, you wouldn't CHECK UP on me !!!"
We've got to have the maturity and clarity of thought to answer with a not-so-obvious answer, like: "If I *never* checked, I wouldn't know how trustworthy you are. I'd always wonder. If you don't test the glue, you don't know how strong a joint it makes. You test it to the point of breakage on smaller/less-important jobs. If you were someday thrust into a serious matter where you needed to take charge, I'd know I could trust you because of this experience of VERIFYING that you were trustworthy in these smaller matters... and I will have done my job."
It depends on how "trust" is defined. If it means "complete faith" or "100% trust", then it's either dishonest or inconsistent to verify. In the case of the teenager and parent above, "trust" apparently presumes a range of trust values, say 0%-100%, and the "not-so-obvious" parental comeback might mean: "Over the years as you grow more capable and honest I continue to trust in you more and more, but it's only on an experimental basis. I always hypothesize you can be trusted with the latest with the latest hurdle or task; you carry out the task; I verify if it seemed to go well; and if it did then you gain or earn relatively more or less of my valuable trust; but if I learn you fail or cheat, I trust you less." It's not obvious if that sort of carrot & stick experimentation is indeed as ethically or even practically sound as might be desired.
For one thing, many wayward and prodigal youths well understand the above variety of carrot & stick parental testing, and clever youths may learn to steadily outwit their parents oftimes poorer powers of verification. In which case the naive verifier parent trusts more and more, but by their own lights, should really trust less and less.
Another way "trust" might be defined is "having a good knowledge of a persons character", which presumes that personal character objectively exists. In this way, one might even safely trust and rely upon dishonest people who are known as such; in such cases the truster might entrust and task their dishonest agent with jobs where their faults would either do no harm, or even be useful. As a family clan crime boss might -- they know a cousin is liar, a thief, or a murderer, and employ them as such, and organize relationships with careful boundaries and cautious secrecy. Spy agencies, detective agencies, undercover police or soldiers, et al, they all have the same basic problems with trust, and must depend less upon experiment, (as verification is a rare luxury), and more on knowledge or theories of character, straight or crooked.
Another kind of "trust" is developed or instinctual sympathy. Some trusters rely on mutual affinity, apart from experiment or character. The trusted and truster may be as fingers of the same hand. Not unlike a faithful dog or horse, the sentimental hunter doesn't automatically lower his esteem for a faithful hound simply because of a failed experiment, rather in such a case the hunter and hound might instead recoil from the failure as evidence of something outside of them both. Hans Christian Andersen's amusing tale "What the Good Man does is Always Right", is about this kind of trust.
So Reagan & Gorby, as well as the father/teen above would seem to lack the latter two kinds of trust (character & sympathy), but still might enjoy the "scientific" variety. "Trust, but verify" is consistent with experimental trust, fuzzy with trust of character, and an oxymoron for sympathetic trust. (e.g. Would Trigger ever betray Roy Rogers?)
The father/teen story has a potential sadness: the teen might remember, "when I was born and toddled, you knew my character and sympathized completely, and vice versa, but with age and many burdens, these bonds withered, and we have experimental trust and its resulting provisional contracts. Someday, our contracts might end with you in a nursing home, and if the end feels guilty we wonder if anything was missing." By this story, I'd suggest that our preferences as to which kinds of trust are practical and best depend somewhat on where and when we floated down the rivers of history.