The answer to the question “What is art?” is contingent on a set of aesthetic judgements.
It strikes me that Plato’s notion of forms and criteria for identifying and/or judging objects to be instantiations of those idealizations is impractical. Philosopher kings might be up to the task, but the majority–us “lesser mortals”–are less schooled, subject to cultural or normative relativism, taste (or the lack thereof), etc.
I think the Wittgensteinian notion of a “family of resemblances”–that there are exemplars and objective criteria for judging things to be “art” is a practical, or shall we say “practicable” way to answer the question.
I mean this in the sense that Justice Potter Stewart tried to explain what hard core pornography is by saying,
“I shall not today attempt further to define the kinds of material I understand to be embraced… but I know it when I see it …”
Given the limitations of my colloquial understanding of art and the vernacular of aesthetics, I’d say that cartoons of Wonder Woman or Thor conform to standards of beauty, strength, color, form (figurative or otherwise) we would ascribe to be works of art.
I understand that neural networks perform at super-human levels of expertise in classifying images, videos, sounds, etc by training them on large sets of data. One of the limitations of search (like Google) is that outputs are conditioned by preferences indicated in prior searches. This is the “echo chamber effect.”
So, I would think the Wittgensteinian approach to training a neural network and, by extension, a person to recognize an object d’art, would be to utilize a wider data set. The dataset would not be filtered by Google search criteria but completely open–using exemplars of art from all cultures, demographics, historical periods, etc. We might call this the “Zeitgeist Data Set.” The outputs of that sort of Zeitgeist process, human or computational, would be more likely to yield a universal YES or NO in regards to the object under consideration.
I think this applies to music as well. Someone once asked Louis Armstrong, “What is jazz?”–to which he relied, “If you has to ask, you never gonna know.”
The quintessential examples of borderline cases of art are the works of Marcel Duchamp. These are the so-called “Readymades.” They were/are ordinary objects put on display as works of art. Many reside in respectable art museums, Though one might argue there’s no accounting for taste.
“Fountain”–a urinal put on display and signed by the artist is a famous example. Here’s a link to a picture of it: https://www.tate.org.uk/art/artworks/duchamp-fountain-t07573.
I also read somewhere that a famous artist (Dali?) once shot himself in a gallery and referred to the act or resulting blood spatter against the wall as a work of art.
When I was a bachelor, I hung a homemade kayak on the ceiling of my den for storage. Most of my friends though it was out of place, but a friend who was a sculptor referred to it as a work of art.
I appreciated that.