I don’t have a Facebook account, but I hear things. One of the recent memes was about how the way you look at a 6 or a 9 determines whether it is a 6 or a 9. The fallacy is then to go to suppose that all things are merely convention, you can’t judge me, etc.
However, the response was equally problematic. Responders suggested that we look around to other number or seek the artist’s intention. This is to take a purely objective position or a hyper-realism.
The intention of the artist is clear that the drawing is to indicate a 6 or a 9 depending on its orientation with respect o the viewer. This is key, because there is no objective fact to whether it is a 6 or a 9. It is simply a matter of convention. Indeed, this is characteristic of human artifacts that they are purely accidental. Whether the pixels on the screen signify a six or a nine is determined by a difference in orientation, that is an accident. There is no substantial reality to it being a six or nine, because this is exactly what the artist intends.
Some things are purely conventional and other things are a mix of the convention or subjective and the objective.