Fit One, Page Six, Panel One

The last of the crew needs especial remark,
Though he looked an incredible dunce:
He had just one idea — but, that one being "Snark,"
The good Bellman engaged him at once.

It's a fair cop, guv'nor! The Bellman, assisted by the Fellowship of the Snark, brandishes his clochetic truncheon at this wallah's stoney noggin. Note further, my dear Watson, that a close reading of the text with a fine-toothed comb and well-knitted brow elicits the following facts:

Given …
The duncedness of this otherwise un-named crewmember is literally not-to-be-believed, a statement which itself is not-to-be-believed since it has not been repeated the requisite three times.
Given …
The sole internal property of this non-nonbelievable dunce is Snark.
From which …
The total epistemology of a dunce is a snark.
And therefore …
To possess a dunce is to possess a ready-made Platonic Ideal of a Snark — and in a very handy demi-godlike package too!
And therefore…
This dunce is no dunce, eh? QED!

So, our dunce is an imposter disguising himself as an Easter Island moia with an uncanny penchant for resembling the notorious French confidence-picturist and double-crosser, Eugène Delacroix! After some rough handling and quick bell-work, the so-called Eugène made the following (internal, hence epistemologically dunciad) statement:

"… one should not be too difficult. An artist should not treat himself like an enemy. Experience ought to teach us two things: first, that we should do a great deal of correcting, secondly, that we must not correct too much."

Proof positive and bob's your uncle! This man's an absolute diabolical numbskull, cunningly fitted out with all the French Polynesian deviltry necessary to hold two simultaneously opposing thoughts at once — the very conditions necessary for a Snark to flourish inside the old brain pan! Pseudo-neoplatonic skullduggery with alarming whiffs of a faux-phrenological sub-gnostic epistemological thing-um-a-jiggery — some sort of game's afoot! I could have had a job with NASA but I'm sticking it out with this snark business, I'm a brainworker!