Perhaps I may venture for a moment to use a more serious tone, and to point out that there are mental troubles, much worse than mere worry, for which an absorbing object of thought may serve as a remedy.
- There are sceptical thoughts, which seem for the moment to uproot the firmest faith:
- there are blasphemous thoughts, which dart unbidden into the most reverent souls:
- there are unholy thoughts, which torture with their hateful presence the fancy that would fain be pure.
Against all these some real mental work is a most helpful ally. That “unclean spirit” of the parable, who brought back with him seven others more wicked than himself, only did so because he found the chamber “swept and garnished,” and its owner sitting with folded hands. Had he found it all alive with the “busy hum” of active work, there would have been scant welcome for him and his seven!
(Charles Lutwidge Dogdgson: Pillow Problems and A Tangled Tale, 1885, p. XV;
see also: Life & Letters. Bulletpoints not by Dodgson.)
As any human, Carroll/Dodgson was battling with all kind of temptations. As we know, speculations about possible temptations in his private life keep feeding the pop culture Carroll debate since the 1930s. The controversy even might marginalize the religious conflicts which the Reverend Dodgson was struggeling with. I think that one of these serious conflicts was Charles Darwin’s challenge to fundamental religious beliefs. Darwin’s discoveries surely had (and still have) the potential to uproot the firmest faith in various religions.
I don’t know to which degree the illustrator Henry Holiday discussed and aligned with Carroll his choice of pictorial references in his illustrations to Carroll’s The Hunting of the Snark, but there is a pictorial reference to mental troubles: St. Anthony’s temptations (painting by Matthias Grünewald). In one of Holiday’s illustrations you see Colenso’s arithmetic textbook. Like Anthony, also Carroll needed lots of mental work as an distraction from sceptical, blasphemous and unholy thoughts. Anthony probably found help in the Bible. Interestingly, the Reverend Dodgson used mathematics to resist the temptations.
I saw this math textbook in Holiday’s illustration since many years. Only recently that led me to the assumption (which probably always will be just an assumption) that Holiday might have placed that book into his illustration as a hint to how Carroll used math to keep his brain busy with “some real mental work” as a “most helpful ally” in his battle against the temptations which haunted him.
By the way: Possible references in “The Hunting of the Snark” to St. Anthony and to Darwin had been addressed by Mahendra Singh already in June 2007, more than two years before I started my Snark hunt. He and John Tufail were among my most helpful scouts during that hunt.
2020-06-11, update: 2020-07-12
Before my Snark hunt started in 2008, I mainly focused on Henry Holiday’s 
