Meaning of "thus much"

Question

Recently, reading Edgar Allen Poe, I came across the phrase "thus much" and am struggling greatly to figure out its exact meaning. The first context in which it's written is in the poem A dream within a dream.

Take this kiss upon the brow!

And, in parting from you now,

Thus much let me avow -

You are not wrong, who deem

That my days have been a dream;

...

The second place in which he seemed to have used "thus much" in such a way was found while searching through the internet yesterday, so I'm just going to copy paste the part of the question from a forum where I'd found this.

I have thought proper to premise thus much, lest the incredible tale I have to tell should be considered rather the raving of a crude imagination, than the positive experience of a mind to which the reveries of fancy have been a dead letter and a nullity.

• Edgar Allan Poe - Message in a bottle

Now, "thus" in the first example could hold a similar meaning to "therefore", but surely he would have used a comma after it then, wouldn't he? "Thus much" in the second example, however, appears to mean something more along the lines of "this much", but again, why wouldn't he just write that instead, were that the case.

Answer 1

It looks like Kate Bunting's guess was a good one. In "this much" and "thus much" the first of the two words seems to be signifying up to a certain degree. The American Dictionary of the English Language (A.D.E.L.), which was written by by Noah Webster and published in 1828 even expressly defines the phrase in his definition of the word Thus, of which the relevant portion is this:

1. To this degree or extent; as thus wise; thus peaceable.

Thus far extend, thus far thy bounds--

2. In the phrase, thus much, it seems to be an adjective, equivalent to this much.

Since the sense of the word I emphasized was the most recently developed in the dictionary, and that Noah Webster and Edgar Allan Poe were contemporaneous countryman, I surmise that it is the one that applies. So if you pretend as if it was written as "this much" you might be less confused while reading.

Answer 2

He wrote it a long time ago, and English changes quickly.

I read it to mean This or The following, as in "Let me avow this" or "Let me avow the following."

Answer 3

OED:

Thus (adv.)

3. Qualifying an adjective or adv.: To this extent, number, or degree; as..as this; so; esp. thus far, to this point (often used to indicate the end of a quotation); thus much, so much, as much as this.

c1369 G. Chaucer Bk. Duchesse 904 But thus moche dar I sayn. (But thus much I dare say.)

a1616 W. Shakespeare Taming of Shrew (1623) i. ii. 103 Therefore let me be thus bold with you.

1823 R. Southey Hist. Peninsular War I. xii. 617 The happy issue, thus far, of their civil administration.

1888 E. A. Freeman in W. R. W. Stephens Life & Lett. E. A. Freeman (1895) II. 374 The legend..has thus much of foundation.

Thus much let me avow - So much let me avow - As much as this let me avow.