I have gradually realised that some of the authors with whom I share the greatest 'fellow feeling' are the aphoristic note-makers. For example: Pascal's Pensees, Novalis's Pollen and Philip K Dick's Exegesis. I have ordered a selection from Coleridge's Notebooks, so we'll see if that can be added to the list...
The main thing about these 'unfinished' works, is that they are the writer actively thinking and talking with himself, as honestly as he is able - and the kind of person who produces this kind of writing is someone who thinks and broods purposively for much of the time.
That is what I recognise and am drawn-to; because I am of this type and have met extremely few people who are like me in this regard.
This activity (ie. spending hours per day brooding and thinking) is the basis of what I would regard as the real and proper activity of Philosophy; and why I called myself 'a philosopher' in my scrappy-memoirs (which are not themselves, however, an example of this notebookish form).
I can remember when I first looked-at Pascal, in a secondhand bookshop in Cheltenham some decade ago. I opened the Penguin paperback, read a few lines; and simply felt: Yes.
I feel the same every time I look at it. In a sense, everything else (content, conclusions etc) is secondary to this affirmative affinity.
This note-taking thinker is a definite, albeit rare, Type; as much as the scientist, poet or fiction writer - and will be the covert driver of those activities: for instance of the poetry of Novalis, the Fiction of PKD, or my science (which was mostly theoretical).
(I may recognise the type, but don't always feel a personal affinity: Nietzsche and Wittgenstein are instances of this. They are my type, but mostly on a different wavelength.)
And it is why I have found blogging (of the type I do) so congenial; because it is only one step removed from my primary work: those reams of handwritten notes I have generated through writing every day for the past (what?) forty-plus years - yet almost never looked-at a second time.
In one sense these notebooks are the meditative-laboratory for my published and disseminated writing; in another sense the public work is secondary to the notebooks; which are The Real Thing (despite that nobody ever will see them, nor would they be of any interest).
The clearest example of this 'real thing' can be seen with PKD's Exegesis compared with the novels he published in the final eight years of his life when he was making notes for it. For one who can appreciate the Exegesis (and is reading from a shared primarily-Christian perspective with PKD, which essentially None of his critics and editors are); it can easily be felt that the notes are primary and the novels (such as Valis - which is a fictionalised version of the notes) are derivative and lesser.
I am not saying that journal-type notes are superior works-of-art to poems, novels, essays; because they certainly aren't. Not even close! They will always be a (tiny) minority taste.
And indeed where they are not - as with Pascal - they are usually adopted pretentiously and grossly misunderstood by people whose nature is extraverted and whose content is externally-derived.
Art is a public activity, by intent; and journaling notes are not - or, ought not to be. The purpose is different. In a nutshell; what I value in these works is evidence of another person whose thinking is endogenous. In finished art is is difficult to impossible to tell whether the writer is generating or channelling the material - and it is almost always the latter.
For example, skilled journalists, critics, popular non-fiction writers take-in material, subject it to standardized-processing, then spew it out. The result may be superficially and temporarily impressive - but is deeply and over the long-term, debilitating. Such writing (for instance much 'travel writing' is a kind of trick - parasitic upon the genuine thought of others.
(The same applies to what passes for science nowadays; most of the most-influential of which is written by agencies who employ glibly-articulate quasi-journalistic hacks and PR merchants to do the job.)
To get back to PKD's Exegesis - this brings out another aspect of this kind of work; which is that it is not done to impress others, nor to satisfy the needs of socialization. Dick was, apparently, a bit of a chameleon in his social interactions; with a tendency to say and behave in ways to gratify the company. This meant there was a considerable gulf between the spontaneous incoherence of his notebooks; and the adjusted and filtered versions of these which appeared in everyday conversation.
Indeed, most of us are like this; we adjust what we say to the person we are speaking with. Sociality is primary. Yet when real, hard, honest thinking is being done' the unfiltered original may have an interest and validity - perhaps greater than the (more-or-less) bowdlerised versions of the ideas that we show to other people.
So a journal written to be shown to other people - like those of Thoreau and Emerson - may well make excellent literature - as these do. But such 'public journals' lack the special quality of genuine, personal notes; when the writer's audience is himself.