“
Spinoza's material life and economic independence were based on the grinding of lenses; in Lasker's life chess played a similar part. But Spinoza was luckier, for his business was such as to leave his mind free and independent; whereas master-chess grips its exponent, shackling the mind and brain, so that the inner freedom and independence of even the strongest character cannot remain unaffected.
— BARUCH SPINOZA