We should seek what we can clearly intuit or deduce with certainty

We should seek not:

• what others have thought or
• what we ourselves have accepted

We should seek what we can clearly intuit or deduce with certainty.

Knowledge is acquired in no other way.

Ancient books must be read because it lets us benefit from the labors of so many people. These let us know:

• those things which were rightly discovered long ago
• what things are still needed to be discovered

However, it is very dangerous in the meantime lest perhaps the stain of errors, contracted by their too attentive reading, adhere to us no matter how unwilling and careful we may be.

Authors tend to make hasty beliefs regarding some disputed opinion. They always try to draw us back to the same place with the most subtle arguments.

On the other hand, whenever they discover something certain and evident, they present it wrapped up in various circumlocutions.

This is because they fear that the dignity of what was discovered by the simplicity of reason might be diminished, or because they envy us the clear truth.

For every opinion, there is a contrary opinion. This makes the people unsure on whom to believe in.

It would be useless to vote for who is correct because the truth is often found by a few people.

Even if the correct opinion was accepted, the teaching of it would not be enough.

This is because we shall never become mathematicians even if we remember all the lectures. We would need also to naturally be able to solve problems with our knowledge.

We shall never be philosophers if we cannot form a stable judgment, even if we read all the arguments of Plato and Aristotle. In such a case, we would have learned histories, not sciences.

No conjectures are ever to be mixed with our judgments concerning the truth of things.

This is important.

Only the obscure things in vulgar philosophy are called into question. This is because the studious:

• are not content with recognizing clear and certain things
• dare to assert even the obscure and unknown by probable conjectures

They then place their full faith these conjectures, confusing them with true and evident things.*

There are only 2 actions of our intellect which lets us know things without any fear of deception:

1. Intuition
2. Induction

Intuition is the easy and distinct concept of a pure and attentive mind.

It is not:

• the wavering belief of the senses or
• the fallacious judgment of an ill-constructed imagination

The conception of a clear and attentive mind, which is so easy and distinct that we cannot doubt what we are conceiving; or again, what comes to the same thing, intuition is the indubitable conception of a clear and attentive mind which proceeds solely from the light of reason."

Thus everyone in mind can contemplate that:

• he exists, thinks
• a triangle has only 3 lines
• a globe has only 1 surface

Moreover, in case someone is moved by the novelty of the use of the word intuition and other things that I am about to be obliged to remove from the common signification in the following, I generally remind myself that

I do not know how exactly “intuition” was used in the past.

I transfer what I mean to that Latin word “intuition” because I have no words for it myself.

But this evidence and certainty of intuition dows not require a method for singular enunciations alone, but also for any discourses.

For example, 2 and 2 make the same thing as 3 and 1.

From these two propositions the third necessarily follows.

Therefore, doubt can arise, why, besides intuition, another method is joined here, which is made by deduction: by which we understand that everything that is necessarily concluded from certain other things known, is.

This had to be done because many things are certainly known but not obvious.

They are made obvious only if they are deduced from the continuous motion of thought of the plainest and most attentive man.

nor otherwise than, if we know the end annular extremity of some long chain and the first connection of it with the same, we have contemplated all the intervening, which depend on that connection, only successively, and remember that they adhere to the next from the first to the last.

Here, we distinguish the intuition of the mind from a certain deduction, from this, that in this motion, or in that the series, as if it were a succession, is conceived;

because the present evident necessity, which is by no means necessary, such as in the intuition, but rather from the memory it borrows its certainty somehow.

This means that those propositions are to be said, which from the first principles are immediately concluded, under a different consideration, now by intuition, now by deduction;

The first principles themselves, only by intuition; and against remote conclusions, only by deduction.

These 2 roads are the most certain knowledge of things by removing suspicions and errors.

nor on the part of genius are more to be admitted, but all other are to be cast away; which yet does not prevent that the things, which have been divinely revealed, the more certain knowledge of all these, with what may be of obscure things, may be believed; for their faith, in whatever they are obscure, is not the action of the mind, but the will; and if in the understanding there are any foundations, they can be found and must be found by one of these ways, as we may show, perhaps, more fully.