The fourth argument [for "sullied"] is of a literary character. Not only is "sullied flesh," as I pointed out ... highly significant dramatically, but in view of the immediate context it is poetically entirely satisfactory.

       ... ["sallied"] credits Shakespeare with a poverty of invention to suggest that the same images were running through Hamlet's head on both occasions [the First and the Fourth Soliloquy]. Now when Shakespeare used "sully" he always had a perfectly definite idea at the back of his mind -- the idea of flecks or spots upon a surface of pure white, an idea, of course, which was readily applied to human character or human beauty. [Here he reviews the few other examples of "sully" elsewhere before returning to Hamlet].

     ... the "slight sullies" which Polonius bids Reynaldo lay upon the reputation of Laertes belong to exactly the same nook of Shakespeare's imagination. And Hamlet's "sullied flesh"? In Hamlet's mouth we should expect something at once more daring and more subtle than in the foregoing instances, and we get it. Look at the context --

     Oh that this too, too sullied flesh would melt,
     Thaw and resolve itself into a dew. [his punctuation]

     "Melt -- thaw -- dew"; there is only one white surface to which these words are applicable. Hamlet is thinking of snow, the snow-white purity of his young manhood, which his mother's appalling crime* has begrimed with foulest soot. Yes, her very flesh, for is he not bone of her bone and flesh of her flesh?

Thus the reading "sullied flesh" is forced upon us not only by bibliographic and etymological considerations, but also because it unlocks the passage in which it occurs and reveals the existence of a shining and hitherto unsuspected jewel in Shakespeare's golden treasury.

Wilson is taken with academic arguments for "sullied" at the expense of the larger picture. Other things being equal, parsimony suggests that, if the evidence for "sullied" is no greater than for "solid," the latter should prevail because of the Folio. Also he commits the logical fallacy petitio principii ("postulation of the beginning" or begging the question). He slides the conclusion of his argument (Shakespeare intended sullied) in among its premises (because Shakespeare could only have been thinking of dirty flesh). It's subtle, but it's circular -- and therefore inadmissible. (His contemporary Bertrand Russell said such tricks have all "the advantages of theft over honest toil.")

Wilson's citations and textual references are correct, although of dubious relevance. His careless punctuation of the couplet doesn't mean much either way about sullied versus solid, but it's ironic to have petty inaccuracies next door to extravagant certitude:  "... highly significant ... entirely satisfactory ... always ... perfectly definite ... of course ... exactly ... only one ...." He knows what must have been running through Hamlet's mind as backdrop to the First and Fourth Soliloquies. And in the First Soliloquy, he knows that Hamlet is thinking of snow and the "snow white purity of his young manhood." Wilson claims not just to read Shakespeare's conscious mind -- not just to peer into the "nook of Shakespeare's imagination" -- but to know what Shakespeare "always" had in "the back of his mind."

While J. Dover Wilson was one of the great Hamlet scholars, he had an inflamed regard for his own opinions. In this instance, his need to find "hitherto unsuspected" gold in an old mine blinds him to the internal connections supporting solid: Viewed with the same lens of textual analysis that he himself used for sullied -- and with no circular reasoning needed -- solid better fits the context.