“The safety-valve of all speculation is: It might be so.
And so long as that might remains, a variable deeply understood, then speculation does not easily become dogma, but remains the fluid creative thing it might be. Thus, a valid painter, letting color and line, observed, sift into his eyes, up the nerve trunks, and mix well with his experience before it flows down his hand to the canvas, has made his painting say, ‘It might be so.’ Perhaps his critic, being not so honest and not so wise, will say, ‘It is not so. The picture is damned.’ If this critic could say, ‘It is not so with me, but that might be because my mind and experience are not identical with those of the painter,’ that critic would be a better critic for it, just as the painter is a better painter for knowing he himself is in the pigment.“
– John Steinbeck,
   Sea of Cortez, p. 265, (1941)

This idea of a personal, perceptual reality
is recurrent in the works of John Steinbeck.  In his preface to East of Eden he wrote, “[The reader] will take from my book what he can bring to it. The dull witted will get dullness and the brilliant may find things in my book I didn’t know were there.”