I’ll take my own bait (from here). I’ll offer one dream vision in tentative support of the idea that some literary genres may develop interesting taxonomies of the sort of wandering thinking that cognitive scientists are interested in at the moment. This is the beginning of Chaucer’s House of Fame. The pose is that the speaker of the poem, completely at a loss to understand the mysteries of dreams, just hopes that God will make things turn out alright. Underlying the modesty, however, there is a lightly-worn expertise in the theory of dreams. Along the way, he gives a whole range of explanations of dreaming, and some key words arise as if casually — ‘reflexiouns’ and ‘impressiouns’ strike me as particularly thought-provoking.
      Its real value as a contribution to the theory of mind-wandering, I think, would come in a nuanced and wide-ranging analysis of many such poems, identifying the particular emphases and deviations. I was tempted, for example, to start with Chaucer’s Parliament of Fowls instead: here the speaker falls asleep after reading Cicero’s ‘Dream of Scipio’ and is then visited by Scipio in a dream. Nice touch, with its own idiosyncratic twist on how and why the mind moves.

God turne us every dreem to gode!
For hit is wonder, ,
To my wit, what causeth
Either on morwes, or on evens;
And why the effect folweth of somme,
And of somme hit shal never come;
Why that is an avisioun,
And this a revelacioun,
Why this a ,
And nat to every man even;
Why this a fantom, these oracles,
I ; but who-so of these miracles
The causes knoweth bet than I,
Devyne he; for I certeinly
Ne can hem noght, ne never thinke
To besily my wit to ,
To knowe of hir signifiaunce
The , neither the distaunce
Of tymes of hem, ne the causes,
For-why this more than that cause is;
As if folkes complexiouns
Make hem ;
Or ellis thus, as other sayn,
For to greet feblenesse of brayn,
By abstinence, or by seeknesse,
Prison, stewe, or greet distresse;
Or elles by disordinaunce
Of naturel acustomaunce,
That som man is to curious
In studie, or melancolious,
Or thus, so inly ful of drede,
That no man ;
Or elles, that devocioun
Of somme, and contemplacioun
Causeth swiche dremes ofte;
Or that the cruel lyf unsofte
Which these ilke lovers leden
That hopen or dreden,
That purely hir
Causeth hem avisiouns;
Or if that spirites have the might
To make folk to dreme a-night
Or if the soule, of propre kinde
Be so parfit, as men finde,
That hit ,
And that hit warneth alle and somme
Of everiche of hir aventures
Be avisiouns, or by ,
But that our flesh ne hath no might
To understonden hit aright,
For hit is warned to ; —
But why the cause is, noght wot I.
Wel worthe, of this thing, grete clerkes,
That trete of this and other werkes;
For I of noon opinioun
as now make mensioun,
But only that the holy rode
Turne us every dreem to gode!
For never, sith that I was born,
Ne no man elles, me biforn,
Mette, I trowe stedfastly,
So wonderful a dreem as I
The tenthe day dide of Decembre,
The which, as I can now remembre,
I wol yow tellen every .