Immethodical

[T]he unſkilful and immethodical teaching of thir paſtor, teaching here and there at random out of this and that text as his eaſe or fanſie, and oft-times as his ſtealth guides him.

Source: wiktionary

I must beg my reader’s indulgence, being the most immethodical writer imaginable. It is true I lay down a scheme, but fancy is so fertile I often start fresh hints, and cannot but pursue them; pardon therefore, kind reader, my digressive way of writing, and let the subject, not the style or method, engage thy attention.

Source: wiktionary

The letter I am looking for was one written by Mr Elliot to him before our marriage, and happened to be saved; why, one can hardly imagine. But he was careless and immethodical, like other men, about those things; and when I came to examine his papers, I found it with others still more trivial, from different people scattered here and there, while many letters and memorandums of real importance had been destroyed.

Source: wiktionary

1844, Edgar Allan Poe, “A Tale of the Ragged Mountains” in The Tales and Poems of Edgar Allan Poe, New York: The Brampton Society, 1902, Volume 5, p. 77, In the quivering of a leaf—in the hue of a blade of grass—in the shape of a trefoil—in the humming of a bee—in the gleaming of a dew-drop—in the breathing of the wind—in the faint odors that came from the forest—there came a whole universe of suggestion—a gay and motley train of rhapsodical and immethodical thought.

Source: wiktionary