treatise, has shut out any hope of my attaining to the charms of which dialogue is capable; but I hope that the matter will make up for the shortcomings of the manner.
  Our disagreements concern points of some importance. There is the question whether the soul in itself is completely blank like a writing tablet on which nothing has as yet been written - a tabula rasa - as Aristotle and the author of the Essay maintain, and whether everything which is inscribed there comes solely from the senses and experience; or whether the soul inherently contains the sources1 of various notions and doctrines, which external objects merely rouse up on suitable occasions, as I believe and as do Plato and even the Schoolmen and all those who understand in this sense the passage in St Paul where he says that GodÕs law is written
49  in our hearts (Romans, 2: 15). The Stoics call these sources Prolepses, that is fundamental assumptions or things taken for granted in advance. Mathematicians call them common notions or koinai ennoiai. Modern philosophers give them other fine names and Julius Scaliger, in particular, used to call them Ôseeds of eternity' and also  zopyra' - meaning living fires or flashes of light hidden inside us but made visible by the stimulation of the senses, as sparks can be struck from a steel. And we have reason to believe that these flashes reveal something divine and eternal: this appears especially in the case of necessary truths. That raises another question, namely whether all truths depend on experience, that is on induction and instances, or if some of them have some other foundation. For if some events can be foreseen before any test has been made of them, it is obvious that we contribute something from our side. Although the senses are necessary for all our actual knowledge, they are not sufficient to provide it all, since they never give us anything but instances, that is particular or singular truths. But however many instances confirm a general truth, they do not suffice to establish its universal necessity; for it does not follow that what has happened will always happen in the same way. For instance, the Greeks and Romans and all the other nations on earth always found that within the passage of twenty-four hours day turns into night and night into day. But they would have been mistaken if they had believed that the same rule holds everywhere, since the contrary was observed during a stay in Novaya Zemlya. And anyone who believed that it is a necessary and eternal truth at least in our latitudes would also be mistaken, since we must recognize that neither the earth nor even the sun