These and cognate questions lie at the foundation of art criticism and of the assessment of the contribution that art can and should make to civic society. How to answer them?
Art, Fiction, Deception
At a first approach, it seems that art is not committed to truth. First of all, art seems to be unrelated to whatever is true of this world. In order to express themselves, artists have to construct an imaginary universe of discourse, a fiction, an illusion, in some cases representing impossibly nice or dreadful scenarios. Artists live in the realm of the possible-that-is-not-actual and it is not a chance that many artists are characterized as dreamers.
Second. In order to move the spectator, an artist seems to be entitled – at least in principle – to a great deal of moves that involve some sort of deception. To deliberately trick the audience in order to achieve the desired effect seems to be permissible in art, as the goal is the one of leading to an experience of beauty, whatever may take to achieve that result. Whether art has some purposes or not, hence, the role of the artist is to prompt an aesthetic experience and it does not matter in what ways such an experience is achieved.
A third, more controversial, point, moreover, is that the value of an artwork is unrelated to any sort of truths surrounding it. Even those truths that relate to how the artwork has been produced. According to this opinion, for instance, the appreciation of the beauty of a statue is unrelated to when and in what manners the statue was produced. All that matters is that the piece elicits an aesthetic attitude in the viewer.
The controversial character of the third point is a signal of the fact that, despite the relationship between art and truth seems not to be so straightforward at first, there is actually a deep connection.
Art as a Metaphor
The ways in which truth can be expressed are multifarious. You need not put it always in a categorical sentence. Humor, for instance, can be a vehicle for the expression of truth, even if the content will typically be expressed by means of exclamations and rhetorical figures. In analogy with comedians, artists arrive at expressing the truth about a certain domain of discourse by using a rhetoric specific to art. In a sense, the truth expressed by a piece of art is metaphorical, in that it purports to say something about the actual world by comparing it to a fictional one.
In The Republic, one of his most famous works, Plato despised of art precisely because it is capable of expressing the truth only through the use of some fiction. No question that the technique is efficacious, and especially so with children. But, to put it bluntly, Plato believes that in the end art tends to create a society of daydreamers. Only art that portraits the world as is, hence, shall be approved.
Art and Authenticity
That the work of an artist is anchored to truth is also clear by a thesis that seems to be shared by most artists: the only way to make good art is to authentically follow your creative drive. Constructing an artwork means to follow a set of rules that you have established and to follow them in a way which will speak genuinely about how you view a subject matter.