Monday, May 10, 2010

Trust but verify is no trust

"Trust but verify" is a phrase made popular by President Reagan. He didn't invent it, yet his use of it in the context of US-Soviet relations made it an oft-quoted maxim.

Logically, the phrase means "don't trust". It can be proven rather simply.

Let "p" be a statement made by someone who you treat with the "trust, but verify" dictum.

Either p is true or ^p is true.

Let's say you verify p independently and find it to be true. At which point you believe p. In this case it is clear that your belief is based not on the original assertion of p but your independent verification of it. You believe "p is true" only after and only because of your verification; it has nothing to do with your trust in that person. Hence in this case, trust doesn't exist.

In the other case, you verify p independently and find it to be false. At this point, you have reasons to believe that ^p is true (through your independent verification) or that p is true (through the assertion of the one who you "trust"). If and only if you choose to believe p in this case, can we truly say you have any degree of "trust"; if you believe ^p, trust doesn't exist.

So the only scenario where we may say that trust exists between two parties is when one of them makes a statement that the other party believes despite there being independent evidence to the contrary.

The question is: when we verify facts independently and they appear to be contrary to the assertion of the one we "trust", are we more inclined to believe the assertion or our findings? My assertion is that we would be much more likely to believe the facts as revealed by our findings; if for no other reason than the expense (time, money) incurred by us is quite compelling. Also, it would be difficult to justify to ourselves that our dearly-held verification process could be wrong and its results could be discarded on occasion.

"Trust but verify" is thinly-veneered, platitudinous nonsense for "don't trust". Trust me on that!