Ignotum per Ignocius

The Canon Yeoman's Tale is a moral one, so far, in my opinion, one of the most clearly moral of all the tales. It is about deceit in art, in words, in life and relationships which "concluden everemoore amys". I don't see the art of transmutation, in this context, as a distinct metaphor for writing but a metaphor for all pursuits which attempt to explain truth. It is the interminable art of multiplication that confounds the beholder but - because of its allure to explain the truth of things - provides a tempting source for hope: "But that good hope crepeth in oure herte/Supposynge evere, though we sore smerte" (lines 870-871). The Canon - whoever he is - can tempt even the most innocent priest into believing in his craft so much so that the priest participates in a kind of witchcraft, renouncing all he should hold dear in the name of god. Fortunately this yeoman, however exceedingly bitter, has seen the truth of the lie, and perhaps even a glimmer of the Truth. He says in lines 842-849:

In lernyng of this elvysshe nyce loore,
Al is in veyn, and parde, muchel moore.
To lerne a lewed man this subtiltee --
Fy! Spek nat therof, for it wol nat bee.
And konne he letterure or konne he noon,
As in effect, he shal fynde it al oon.
For bothe two, by my savacioun,
Concluden in multiplicacioun

This learning (any learning?) concludes in multiplication meaning it concludes by never concluding, never distilling itself into one pure, rarefied thing. There's no gold to come. Gold is gold and coal is coal. That's all the learning that is made finally. But men are not made of gold; they are made of carbon, more like coal. And since we have an unmitigated desire for our own bodily transmutation - perhaps through Christ - we seek it out, this power, in ourselves to no avail. And we look to the philosopher to enlighten us but also to absorb our disdain for his craft. He/She is expected to carry the burden of human confusion but simultaneously be rid of it. The philosopher (whatever form he/she takes: writer, artist, politicain, etc.) is both indispensable and meaningless. The Yeoman has mostly words of spite for the philosopher, however, he/she is a bit rectified at the end: honor restored to the philosophical pursuit. It is at this point that Plato is brought into the scene, who, famously was a philosopher of the spirit, of the intellect and he has the penultimate word:

The philosophres sworn were everychoon
That they sholden discovere it unto noon,
Ne in no book it write in no manere.
For unto Crist it is so lief and deere
That he wol nat that it discovered bee,
But where it liketh to his deitee
Men for t'enspire, and eek for to deffende
Whom that hym liketh; lo, this is the ende. (lines 1464-1471)

So the secret is something protected by Christ, by god himself and philosophers are its keepers here on earth but they are sworn to "discovere it unto noon" and can only describe it by multiplying the message, describing the unknown with more unknown. We ought not to look to the philosopher for the answers, not only because he won't tell us but because he is incapable of doing so. We must seek an explanation for ourselves. And wherever we look, we must be careful not to believe anything too innocently.

The Canon's Yeoman is subdued:

Thanne conclude I thus, sith that God of hevene
Ne wil nat that the philosophres nevene
How that a man shal come unto this stoon,
I rede, as for the beste, lete it goon.
For whoso maketh God his adversarie,
As for to werken any thyng in contrarie
Of his wil, certes, never shal he thryve,
Thogh that he multiplie terme of his lyve.
And there a poynt, for ended is my tale.
God sende every trewe man boote of his bale!

At last the Yeoman essentially says, since god will not allow the philosophers to name the secret, it is best to give it up if you are not a philosopher, but all one can hope is for god to grant each deserving man "boote of his bale" or as the notes explain, a remedy for his suffering. There's only one thing to remedy man's spiritual suffering and that's philosophy.