Reasoning.

Knowing by accident: given that the premises and the conclusion are by accident. Since being a Musician is not inherent to Man, but by accident; and this knowing is not true knowledge. original: "Sapere per accidente." In Aristotelian logic, an "accident" is a quality that isn't essential to the definition of a thing—like a man being a musician. ADRI. From what you have said, then, we can say that the first way is true knowledge: but not the second. GIOS. It is true: but this first way is also of two sorts: for one is called Knowing simply, and the other Knowing in a certain way. The first of these is knowing the conclusion by means of its proper and immediate cause: and the second is Knowing by means of some sign: or by some effect: or truly by some universal and remote cause. FRAN. I desire an example of one and the other manner.

GIOS. Of the first manner it would be: when we know Man to be capable of laughter, because he is rational: Rationality the ability to reason is the proper and immediate cause of Risibility, or of Laughter, as we may call it. Of the second: when we know that a woman has given birth because she has milk: since having milk is not a certain sign that always demonstrates that the woman has given birth. Especially because many women are found to have milk: and yet have not given birth. And not only women: but also (to tell you something that perhaps will seem incredible to you) I have seen men who have milk: and for this one cannot say they have given birth, just for having milk. Zarlino is likely referring to rare cases of male lactation, which was a subject of curiosity in Renaissance medical texts. CLAV. This is indeed a rare thing. FRAN. And because I have understood it all very well, please continue.

GIOS. I say then that the Demonstration made in the first way produces knowledge in itself simply and in a most perfect way: but that made in the second way produces knowledge in itself only in a certain way and very imperfectly: as you have been able to understand from the examples given above. ADRI. Tell us then what this Knowledge is. GIOS. Take heed that I do not wish to define Knowledge taken universally, according to all those ways that I have declared above: but according to that which I name Knowing in itself, simply and in a most perfect way: of which this will be its definition. Knowledge is knowing the thing through its cause, by which it exists: and it cannot be in any other manner. original: "Il Sapere è conoscer la cosa per la sua cagione..." This is a classic Aristotelian definition of scientific knowledge (episteme). And note, that I have said that Knowledge is knowing the thing through its cause: so that from this you may understand that I do not mean Knowledge from the effect: rather I want you to know that I come to distinguish the former from the latter. I added then: by which it exists: making you aware that such a cause is proper and not common to that thing and to another: so that from this you can know how different the Knowledge is that I mean above, from that which comes to be acquired from a universal and remote cause.

For when we know that a stone, or a piece of dry wood, does not breathe because it has no soul: such Knowledge does not spring from proper and nearby cognition: given that many animals are found—such as trees, oysters, worms, flies, and infinite other imperfect animals—which do not breathe. In the 16th century, plants (trees) were considered "imperfect animals" because they possessed a vegetative soul. But the proper and nearby cause of not breathing is that they do not have lungs. Therefore, when I say: and it cannot be in another manner: such an addition is so that you may know such a cause to be infallible and necessary: and also so that you may know the Knowledge that is acquired by means of probable signs: such as when we know that the sick person must be cured: because he has clear urine: eats with appetite: sleeps sweetly: and does other similar things, in such a way that these actions resemble those of a healthy person. And this sign at times is very deceptive: for often the opposite occurs. FRAN. It is necessary then that the cause, by means of which we simply know anything, must be necessary.

GIOS. So it must be: because it is the middle of the conclusion. And because that which is to be known, and Science, are correlative and corresponding to one another: it is necessary that just as the cause of Knowledge is necessary: that also necessary must be that which is to be known: which is the conclusion. For we cannot simply know a conclusion which can happen by chance, which is called Contingent: Contingent something that may or may not happen, not bound by necessity but we can indeed have an opinion of it. ADRI. All these things up to here we understand very well. GIOS. We shall pass then to the Instrument of the intellect, to Knowing and to the acquiring of Science: and we will leave off defining Demonstration universally taken: just as we have also set aside the definition of Knowledge universally: and we will come to the definition of the Demonstration which is called by the Philosophers Most Powerful: original: "Potissima." In logic, a Demonstratio Potissima is the highest form of proof, showing both that a thing is and why it is. and it is that which causes in us Knowledge of the thing defined. Adding—