"I trust him implicitly." Why "implicitly?"

[Frylock]

What’s the origin of the use of term “implicitly” to describe a degree of trust?

And is that usage older or newer than the usage of the term to mean “not explicitly*?” I would think newer, but hey you never know with etymology…

-FrL-

*Not the best definition, but hopefully you see what I’m talking about. I’ve never heard anyone say they trust someone “explicitly” though I’m going to do so at my first opportunity now that I’ve thought of it.

[Don26]

unquestioning or unreserved; absolute: implicit trust; implicit obedience; implicit confidence.

the Second definition at Dictionary.com
Aside from that, I’ve got nothin’…

[Jeff_Lichtman]

I think it’s a case of semantic drift. The first definition of “implicit” at yourDictionary.com is “implied or understood though not directly expressed.” Under this definition, implicit trust is trust that isn’t stated. From there you can go to trust that doesn’t have to be stated, and finally to trust that doesn’t have to be questioned.

[chrisk]

I’m not sure of the exact origin, but I always thought of it as the reverse of “I trust him, but only to the following extent or degree: …” That’s explicitly laying out the parameters of trust.

From there, it seems a fairly natural reversal to ‘implicit’ being ‘without qualification or reservation’

[rowrrbazzle]

From the OED:

3. With implicit faith, confidence, submission, etc.; unquestioningly.

1650 HOBBES De Corp. Pol. 132 There may be more Obedience required in him that hath the Fundamental Points explicated unto him, than in him that hath received the same but implicitly. 1662 J. DAVIES Mandelslo’s Trav. 96 The young Prince implicitely crediting what was told him by his Favourite. 1712 STEELE Spect. No. 497 {page}1 They would lay by their animosities implicitly, if he bid them be friends.

[danceswithcats]

Online etymology states:

implicit
1599, from L. implicitus, later variant of implicatus, pp. of implicare (see implicate).
implication
“involvement, interweaving,” c.1430, from L. implicationem (nom. implicatio) “interweaving, entanglement,” from implicatus, pp. of implicare “involve, entangle, connect closely,” from in- “in” + plicare “to fold” (see ply). Implicate in the sense of “involve a person in a crime, charge, etc.” is from 1797.

From that, my sense of it is that implicitly refers to the closeness which one feels towards another, justifying the trust imbued in said party.

Samclem or another more linguistically learned soul may happen along and say I’m full of it.

[SCSimmons]

@Jeff Lichtman

The first definition of “implicit” at yourDictionary.com is “implied or understood though not directly expressed.” Under this definition, implicit trust is trust that isn’t stated. From there you can go to trust that doesn’t have to be stated, and finally to trust that doesn’t have to be questioned.

From said sequence, one can deduce that a statement of implicit trust is necessarily false …