"The greatest discoveries are not made by chance, but by observation and reflection."

"The true philosopher is he who knows how to doubt."

"Nothing is created, either in the operations of art, or in those of nature; and it may be considered as a general principle that in every operation there exists an equal quantity of matter before and …"

"The art of drawing conclusions from experiments and observations consists in evaluating probabilities and in judging if they are great enough to constitute proofs."

"It is only by means of experiments that we can arrive at the truth."