From Salvador de Madariaga‘s Don Quixote: An Introductory Essay in Psychology, a book that has sadly been out of print (in English, at least) since 1948. It is better known for the concluding chapters on how Don Quixote and Sancho reciprocally reshape each other over the course of the novel, but the portions on the tensions underlying Cervantes’ creative style are almost as rich. First a summary statement (pg. 12)
It is well to remember that in Cervantes, as in almost every other Spanish genius, there is as pronounced lack of harmony between the critical and the creative faculties. As a creator, Cervantes is one of the freest men of genius in the world of art. As a critic, his mind is both guided and fettered by classical and academic ideas which merge into hard literary dogmas, as it were, without warning. The two tendencies appear almost inextricably mixed in his attitude towards Books of Chivalry.
and here a more fully explored version of the same (pg. 46-48):
[Cervantes] had in him a royal measure of natural creative spirit; he had also a strong critical prepossession and rather fancied his scholarship, as witness the somewhat naive remarks on translations which he puts in the mouth of Don Quixote when the Knight is visiting the Printing Works in Barcelona. He was endowed with at least the usual amount of sensitiveness to criticism; lastly he worked, as it were, under the eyes of a host of rivals eager to find a flaw. His natural self-consciousness was therefore exacerbated by the conditions under which he was working. And the point is important, for the main effect of self-consciousness in creative work is that it hinders the fusion of the elements which enter into the composition and prevents their blending into an harmonious unity.
Hence the complexity of Don Quixote as a literary work, for in it the diverse currents of influence which acted upon Cervantes at the time of writing appear flowing, as it were, side by side, and may be traced to their different sources. The most important of all, that which gives the work its immortal value, is the creative spirit of the race, as manifest in Cervantes’ predecessors, and particularly in La Celestina. When Cervantes is in this vein he is at his best. Then his observation is so acute, his style so terse and clear, that the work is as reality itself to us. It is the vein of most of the dialogue scenes between Don Quixote and Sancho. Cervantes is here the unprejudiced and spontaneous creator, the impartial observer and lover of men, whatever their condition, rank, virtue; the born writer who never sets down a word that is not living; the free artist who knows nothing but reality seen through emotion; the ideal poet, in whom the ever romantic imagination is instinctively guided and tempered by the ever classic common sense.
And now and then the learned gentleman with literary ambitions puts in a word. Then Cervantes tries to vie with the wits of Italy; He seeks the strange plot; he tries his hand at daintily twisted phrases; he courts the elusive metaphor. When this will-o-the-wisp gets hold of his fancy it is the curious paradox of this most wonderful book that Cervantes seems to forget the very principles of classical order which he so admirably applies when under a spontaneous creative inspiration. Left to itself, his creative imagination, though romantic by nature, is classical in its sobriety, in the economy of its means, in the admirable restraint of its conception and expression. Hustled by his pseudo-classical conceits, this imagination which we saw so true and clearsighted, seems to lose touch with the earth and indulge in extravagant and fanciful evolutions; matter and style become elaborate and needlessly complicated, and Cervantes is then as extravagantly romantic as he was severely classic when writing under the influence of his classical prepossessions.
In writing his Don Quixote, Cervantes meant to break a lance in the cause of simplicity. And, in fact, his style is a model of simplicity but only when he forgets all about it…