Please note that I sometimes return to this article and make slight updates as I gather more information and can better clarify my thoughts on the subject.
In my opinion, with regard to aesthetics beauty isn’t necessarily subjective.
While not entirely, beauty is closer to objective than commonly believed. Is a Ferrari a beautiful car? Are Margot Robbie and Brad Pitt not beautiful actors? Are Redwoods beautiful trees? What about the first steps of a child? My argument is that while subjectivity persists, there are many attributes of beauty shared among subjects that commonly convey to human perception the sensation beauty. I'm obviously omitting certain visually literate aesthetes who may have acquired a kind of taste that allows them to poetically articulate beauty within seemingly mundane subjects. So what are the consistent traits that lead to creating this sensation? There are likely exceptions derived from the context of the viewer. An individual who has been nurtured to view beauty in a specific kind of way and not others due to their learned environment, when encountering a subject divergent from their previously constructed model may not find qualities differing from their nurture, beautiful. So perhaps, instead of saying "beauty is subjective" it's more accurate to say: that beauty is relative, to the individual and to the culture. The plurality of beauty I think is what throws subjectivity into question. This view may be interpreted reasonably as an expansion on the popular saying in English: "beauty is in the eye of the beholder."
THE VALUE OF BEAUTY
Provided with examples, 100% of people may never actually agree or even be aware of the level of beauty intrinsically present within a given subject matter in question. This is not about aesthetic taste present among those visually indoctrinated and those less informed. Instead, the subject matter discussed here involves almost exclusively that which is naturally innate within everyone who is capable of some sensory experience. Joy and appreciation for some are learned reactions to this sensation.
If what I’m positing contains some truth, then it inevitably presents a perplexing question that has likely been asked either abstractly or literally, for thousands of years: what exactly creates the impression of beauty? For the sake of brevity, I'm confining my interpretation of this achievement specifically to the design process but surely it relates to other disciplines and attributes of perception. At the time of writing, I have yet to heavily research the science behind the perception of beauty but I would not be surprised if there are neurological and evolutionary explanations for human appreciation of certain qualities.
Harmony falls within a spectrum—relative to the culture, volition, context and visual vocabulary—of the observer. Denoted in literal musical terms it refers to "...simultaneous notes which produce pleasing effects." Harmony is the causal instrument from which some form of emotive pleasure is derived by the interpreter. Just because something is pleasing however, does not necessarily make it beautiful. Even disharmony is a valuable tool for fostering appreciation for preceding or subsequent harmony. Similar to great musicians, it's possible for visual composers to create form that moves rhythmically to achieve various sensations at unique moments.
So how does one create harmony? By establishing patterned consistency between subject matter and the considered context of the observer to create a pleasure—or more aptly put at times—a subconscious appreciation or provocation which is present only due to a lack of inconsistent disharmony.
Harmony in truth, is often times if not always an objective occurrence through which some observable tactics may be identified independent of subjective observation. Taste is calibrated by culture.
I think as a concept and in more literal terms this idea is more commonly and simply discussed as "consistency" and "inconsistency."