Quotes: William Billings & Rules for Composition

I'm reading a book called "William Billings of Boston", (about the great hymn & psalm composer, essentially America's first composer, & one with a real voice.) The authors point out that it was the conservative elders who, earlier in the 18th Century, established the singing-schools, to educate the masses how to read music & sing the English hymns right (things were getting kind of folksy & enthusiastic); & it was this singing-school movement ("ironically" they point out) that made it possible for some of the more adventurous hymns that the New Englanders in the 1770s-1800 produced. The book's pretty dry, but there's some good quotes about the controversies surrounding music in the colonies:

The singing of Psalmes, tho it breath forth nothing but holy harmony, and melody: yet such is the subtilty of the enemie, and the enmity of our nature against the Lord, & his wayes, that our hearts can finde matter of discord in this harmony, & crochets of division in this holy melody.

-The Whole Booke of Psalmes
(Cambridge [Stephen Day], 1640), p. [1] of preface.

Where there is no Rule, Men's Fancies (by which they are govern'd) are various; some affect a Quavering Flourish on one Note, & others upon another which (because they are Ignorant of true Musick or Melody) the account a Grace to the Tune; & while some affect a quicker Motion, other affect a slower, & drawl out their Noted beyond all Reason; hence in Congregations ensue Jarrs & Discords, which make the Singing (rather) resemble Howling.

-A Brief Discourse Concerning Regular Singing
(Boston: B. Green, Jr. for John Eliot, 1725), pg. 7

William Billings published The New-England Psalm-Singer in 1770 at age 24, with a Hundred-Twenty-Something original compositions--, that increased more than tenfold the amount of American-written music ever published in America. In the preface, he defends some of his unconventional harmonies (illegal parallel fifth & octaves, et cetera); in a time when puritan music was supposed to be somber, he had a lot of explaining to do.

Perhaps it may be expected by some that I should say something concerning Rules for composition. To these I answer that Nature is the best Dictator, for all the hard dry studied Rules that ever was prescribed, will not enable any Person to form an Air any more than the bare Knowledge of the four and twenty Letters, will qualify a Scholar for composing a Piece of Poetry, or properly adjusting a Tragedy, without a Genius. It must be Nature, Nature must lay the Foundation, Nature must inspire the Thought.

-William Billings, New-England Psalm-Singer (Boston, 1770), pg. 19

I have read several Author's Rules on Composition, & find the strictest of them make some Exceptions, as thus, they say that two 8s or two 5ths may not be taken together rising or falling, unless one be Major and the other Minor; but rather than soil the Air, they will allow that Breach to be made, and this Allowance gives great Latitude to young Composers, for they may always make that Plea, and say, if I am not allowed to transgress the Rules of composition I shall certainly spoil the Air, and cross the Strain that Fancy dictated.
-ibid.

For my own Part, as I don't think myself confin'd to any Rules for Composition laid down by any that went before me, neither should I think (were I to pretend to lay down Rules) that any who come after me were any ways obligated to adhere to them, any further than they should think proper: So in face, I think is best fr every Composer to be his own Carver. Therefore, upon this Consideration, for me to dictate or pretend to prescribe Rules of this Nature for others, would not only be very unnecessary, but also a great Piece of Vanity.
-ibid,