Important.

David, Self-Portrait, 1794

In the arts the way in which an idea is rendered, and the manner in which it is expressed, is much more important than the idea itself. The artist must be a philosopher. Socrates the skilled sculptor, Jean-Jacques the good musician, and the immortal Poussin, tracing on the canvas the sublime lessons of philosophy, are so many proofs that an artistic genius should have no other guide except the torch of reason.

Jacques-Louis David