Solution 1:

This is about as silly an argument as I have ever encountered in Shakespearean scholarship — even sillier than the celebrated Impediment of Adipose.

Jonson's compliment is a fairly pretty one: “Despite your lack of a Classical Education (like Mine), your work commands the admiration of the Classical Masters.”

But the reading Ingleby urges makes no sense at all: “Even if you lacked a Classical Education (like Mine), your work would command the admiration of the Classical Masters — all the more impressive, then, that you achieved this in full possession of a Classical Education.”

Jonson was an arrogant and hot-tempered SOB, but he was not an imbecile.

Solution 2:

And though thou hadst means "although you have", and is read the same way today as two centuries ago. I am no scholar, but I don't think it the subjunctive, but merely the indicative.

As you know, the subjunctive expresses a wish, a suggestion, a command, or a condition that is contrary to fact (today... and then?)

  • Would I were sleep and peace, so sweet to rest!
  • I would thou hadst my bones, and I thy news.
  • Would none but I might venge my cousin's death!

Johnson isn't wishing that Shakespeare had more or less learning in Latin and Greek. He's making an observation.

Here's another man's take on "And though thou hadst small Latin and less Greek..."

By being so long in the lowest form I gained an immense advantage over the cleverer boys. They all went on to learn Latin and Greek and splendid things like that. But I was taught English. We were considered such dunces that we could learn only English. Mr. Somervell -- a most delightful man, to whom my debt is great -- was charged with the duty of teaching the stupidest boys the most disregarded thing -- namely, to write mere English. He knew how to do it. He taught it as no one else has ever taught it. Not only did we learn English parsing thoroughly, but we also practised continually English analysis... Thus I got into my bones the essential structure of the ordinary British sentence -- which is a noble thing. And when in after years my schoolfellows who had won prizes and distinction for writing such beautiful Latin poetry and pithy Greek epigrams had to come down again to common English, to earn their living or make their way, I did not feel myself at any disadvantage. Naturally I am biased in favour of boys learning English. I would make them all learn English: and then I would let the clever ones learn Latin as an honour, and Greek as a treat. But the only thing I would whip them for would be not knowing English. I would whip them hard for that. - WinstonChurchill

Now, would that a fair linguist come and show to me the error of my ways.

Solution 3:

Does "And though thou hadst" here mean "And even if you had" or "And although you had"—or is it impossible to tell?

I think it's impossible to tell: because although "hadst" is the subjunctive, it's also the indicative.

If it is impossible to tell, were listeners and readers in Shakespearean/Jonsonian times accustomed to having to draw their own conclusions about whether the subjunctive mood or the indicative mood was intended in such cases?

I suspect that it's an artifact of the poem: "Even if thou hadst" doesn't scan as well as "And though thou hadst".

Had he sought to speak more plainly, that were permitted e'en by the language of his time: yet he chose the more poetic turn of phrase.

Because it fits the verse so well, I think "the sceptic" cannot even prove whether he meant it to be ambiguous.