> Thus, the subjective component is associated with some private habits that can be changed, and the objective – with the general psychophysical features of a human's vision, which we do not assume is possible to change. Therefore, when talking about optimizing the text of a program, it makes sense to talk only about the objective component of readability, and therefore further in this article, the term readability will always refer to this component of it.
Although this separation may be necessary to set the scope for the rest of the text, a lot of which is about cognitive processes that are "wired" into the human visual system and cannot be changed by learning, the above somehow not ringing true for me as a generality and detracts from the text.
Why it isn't ringing true has less to do with the subjective/objective separation per se and more with the author's relegation of learned skills into the realm of what is "subjective".
When people acquire skills, and that makes some tasks easier compared to untrained people, that difference categorically is not subjectivity. It is not subjectivity because we can reproduce the training effect in person after person, and even measure it with some kind of numbers that we can plot on nice graphs and see things like that similar "learning curves" are consistently reproduced in different people.
When we optimize we cannot discount this "subjectivity". We must assume it. We must assume it because the purpose of optimizing the activity, such as reading code, should be geared toward someone who will be doing it a lot. Someone doing the activity a lot will learn something, whether we like it or not, and that learning will reduce their difficulty.
To use a code optimization analogy, modeling the human as static is like generating code based on the machine not having branch prediction or caching.
I think the subjectivity we should discount is in how we measure readability. If we, say, ask subjects to rate the readability from 1 (very poor) to 5 (very good), that is subjectivity we might not want.
Lastly, if you're going to tell the reader you won't be discussing subjective aspects, then it behooves you to subsequently refrain from wording like "the program text often looks like one poorly structured massive chunk" and "placing the last open brace at the end of the line looks quite natural, and the resulting space only adds a small accent, compensating for the small visual mass of the last block".