I didn't see that post as self-indulgent, just a bit rhapsodic, which was somehow an ironically apt tone for the idea that we do things for no real reason but then cling to our justifications.
I have a hard time really buying that idea. I'm sure that sometimes we do things on random impulse, but I think that we also do sometimes act on deliberate plans and principles. More often than either, probably, we do things for definite reasons that just aren't the reasons we think about consciously. In all cases, even the deliberate plans, we are certainly prone to revising our reasons in memory, to make a better story out of the way things turned out.
Probably because of all Morley's birch trees, I found myself remember Frost's poem The Road Not Taken.
Robert Frost wrote:Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;
Then took the other, as just as fair,
And having perhaps the better claim,
Because it was grassy and wanted wear;
Though as for that the passing there
Had worn them really about the same,
And both that morning equally lay
In leaves no step had trodden black.
Oh, I kept the first for another day!
Yet knowing how way leads on to way,
I doubted if I should ever come back.
I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I—
I took the one less traveled by,
And that has made all the difference.
A lot of people seem to remember this poem as being about "the road less traveled" but it's really about how we fall for our own justifications. The poem says clearly that the road taken was not
actually any less traveled, and that the idea that it was less traveled was simply an invented excuse. The conclusion is the prediction that this invented excuse will be enshrined in memory as a grand principle.
Re-reading Frost's poem, though, I think it offers a further clue about why we make arbitrary decisions and invent justifications. In the poem there actually is one real difference between the two roads. The road the traveler doesn't take is the one down which they look for a long time, before taking the other one without looking at it for nearly so long. This gives me the idea that the first road looked disappointing. It didn't really seem to go anywhere interesting, at least not anytime soon. The second road looked so similar that the traveler was afraid that it would be just as unimpressive, if it were studied at length, leaving the traveler with a dismal choice between two equally uninspiring directions.
I think this is a subtle problem in game theory. If the traveler were somehow unable to study the second road carefully—a bear was approaching, or something—and had to choose a road after studying only the first one, the second road could be a rational choice, assuming that neither road could actually be dangerous. The first road was known to be unpromising, while the second road still had a chance of being interesting.
So now step back one level, assuming that no bear is actually coming, and consider the game theory of whether or not to study the second road. If you don't study it, then you get to make a good, rational choice between the roads (as just explained). If you study it, on the other hand, the best outcome is no better (you see something that makes the second road a rational choice) while the worst outcome is worse (you see nothing better about the second road so you're stuck with a difficult choice between equally unexciting options). And the quick glance that you have already given the second road makes the worse outcome seem more likely. So you get to make a choice about which you can feel good if you deliberately avoid studying the second road carefully, and just set off along it without further thought.
If you spin this to yourself as a principled choice of the less-traveled road, you even get to feel optimistic about your randomly chosen journey. On the other hand, though, the second road actually is less traveled in one sense. Your own surveillance has not traveled it by looking down it. So perhaps the poem really isn't just cynically mocking our pretences to principle, but earnestly advocating a principle of taking less-traveled roads, as a metaphor for not overthinking our choices.