Delicately, with the tips of our fingers, let us re-establish the natural order of affairs and spread out flat the ribbon of the twisted leaf-stalk. A surprise awaits us. The untwisted ribbon, replaced in its normal position, is upside down; it shows on the top what ought to be underneath, that is to say, the pale surface, rich in stomata and deeply veined; it shows underneath what ought to be on top, that is to say, the green, smooth surface, as is the rule with all other plants. In short, the Inca lily, when we forcibly restore the natural arrangement by undoing its torsions, has its leaves upside down. What was made for the shadow faces the light, what was made for the light faces the shadow. In this contrary arrangement, the functions of the leaves become impossible; and so the plant, to correct this defective order, twists the necks of all its leaves by the spiral deformation of the leaf-stalks. The rays of the sun provoke this reversal. If we intervene with our artificial devices, they may undo what they did at first. With the aid of a light prop and a few ligatures, I bend a shoot of the lily and fix it head downwards. As a result of exposure to the sun, the leaf-stalks in a few days’ time untwist themselves and become flat ribbons, which turn their smooth, green sides towards the light and their pale, veined surface towards the shade. The torsion has disappeared, the normal direction of the leaves is restored, but the plant is upside down. In the case of the Inca lily, with its leaves set the wrong way round on the stem, are we confronted with a blunder which the plant, aided by the sun, does its best to correct by twisting its leaf-stalks? Are there such things as organic frivolity, mistakes, the signature of disorder? Is it not rather our ignorance of cause and effect which regards as erroneous what is actually correct? If our knowledge were greater, how many discordant notes would become harmonious! And so the wisest course is to doubt. Of all the signs which we employ in writing, the one most nearly resembling the idea which it expresses is the note of interrogation. At the bottom, a round speck: the ball of the world. Above it, twisted into a great crozier, is the lituus of antiquity, the augur’s wand interrogating the unknown. I like to regard this sign as the emblem of science in perpetual colloquy with the how and why of things.