Moonlight shone brightly outside the window. Georgiana sat by the bathtub in a robe, touching the hot water and flower petals with her hand. Her reflection rippled across the surface.
Because its content was too obscure, Kant's Critique of Pure Reason had not sold well. Both hot water and red roses belonged to judgments of The Day After Tomorrow. Her eyes saw the red roses; the roses were red. Her hand touched the water and felt that it was hot. Yet there was no necessary connection between the two. Roses did not have to be red, and water did not have to be hot. There were white swans, but there were also black swans. Such accidental "truths" lacked universality. Before black swans were discovered, people "universally" believed that swans were white. "All," "necessary," and "always" did not point to anything within experience. After black swans were discovered, the unshakable belief that "all swans are white" was shattered.
Once people knew black swans existed, it was unacceptable for anyone to say, "Swans must be white." When knowledge or belief encountered stubborn experience, the truth value of certain statements had to be reassigned.
In the past, human understanding had always conformed to the objects being understood. But mathematical formulas were not swans. 1+1=2 was conditional. If one drop of water was added to another drop of water, the result was not two drops, but still one drop. Should people change the mathematical formula 1+1=2 because of that?
In arithmetic, even children knew to count on their fingers. In that sense, 1+1=2 was intuitively self-evident.
If scientific knowledge was founded on experience, then it possessed no universal necessity. If scientific knowledge possessed universal necessity, then it should not be founded on experience. Kant proposed a new theory: the transcendental preceded experience. The "prior"