But what then am I? A thing that thinks. What is that? A thing that doubts, understand, affirms, denies, wills, refuses, and that also imagines and s… - René Descartes

The passions, then, can be defined as ‘perceptions, or sensations, or emotions of the soul that we refer (rapportons) particularly to the soul itself, and that are caused, sustained, and fortified by some movement of the spirits’ (§27).

Those who possess
the strongest reasoning and who best order their thoughts in order to
make them clear and intelligible can always best persuade others of what
they are proposing, even if they were to speak only Low Breton and had
never learned rhetoric.

The majority of men is composed of two classes, for neither of which would this be at all a befitting resolution: in the first place, of those who with more than a due confidence in their own powers, are precipitate in their judgments and want the patience requisite for orderly and circumspect thinking; whence it happens, that if men of this class once take the liberty to doubt of their accustomed opinions, and quit the beaten highway, they will never be able to thread the byway that would lead them by a shorter course, and will lose themselves and continue to wander for life; in the second place, of those who, possessed of sufficient sense or modesty to determine that there are others who excel them in the power of discriminating between truth and error, and by whom they may be instructed, ought rather to content themselves with the opinions of such than trust for more correct to their own reason.