There is something in painting which cannot be explained, and that something is the essential. You come to Nature with your theories, and she knocks … - Pierre-Auguste Renoir

If I was accused of neglecting my art, or sacrificing my ideas for the sake of stupid ambition, then I would understand the critics; but as that isn't the case, there is nothing to be said. I sent a picture to the Salon for purely commercial reasons. Anyway, it is like some medicines – even if it does no good, it does no harm. [other impressionist artists then refused to send in their work to the Salon]

Nature abhors a vacuum, say the physicists. They could complete their axiom by adding that it has no less a horror of regularity.
Observers know in effect that in spite of the apparent simplicity of the laws which preside at their formulation, the works of nature are infinitely varied, from the most important to the least...
At this time when our French art, still at the beginning of this century so full of penetrating charm and exquisite fantasy, is perishing because of regularity, dryness, and the mania of false perfection that now tends to make the unadorned cleanliness of the engineer into the ideal, we think it is useful to react promptly against the mortal doctrines which threaten to annihilate it...

The so-called 'discoveries' of the Impressionists could not have been unknown to the old masters; and if they made no use of them, it was because all great artists have renounced the use of effects. And in simplifying nature, they made it all the greater.