Art critic Clive Bell (1881-1964) wrote a powerful, small volume, his ars poetic, in 1913, simply titled, Art. In a chapter on modern art's debt to the painter Cezanne, Bell applies his formalist proposals to the example of Cezanne's life, claiming the painter's work is significant due to his conscious intent to be only an artist.
I will paraphrase the end of Bell's chapter, as if he is giving advice to young designers: "To be a designer, for the designer, ought to suffice. Too many designers have become less by trying to become something else."