Discourse on Method and Meditations on First Philosophy
And, in fine, of false sciences I thought I knew the worth sufficiently to escape being deceived by the professions of an alchemist, the predictions of an astrologer, the impostures of a magician, or by the artifices and boasting of any of those who profess to know things of which they are ignorant.
Be that as it may, there is fixed in my mind a certain opinion of long  standing, namely that there exists a God who is able to do anything and by whom I, such as I am, have been created. How do I know that he did not bring it about that there is no earth at all, no heavens, no extended thing, no shape, no size, no place, and yet bringing it about that all these things appear to me to exist precisely as they do now?
c'est une vérité très certaine que, lorsqu'il n'est pas en notre pouvoir de discerner les plus vraies opinions, nous devons suivre les plus probables
partie 3, para 3)
partie 3, para 3)
entre plusieurs opinions également reçues, je ne choisissais que les plus modérées, tant à cause que ce sont toujours les plus commodes pour la pratique, et vraisemblablement les meilleures, tous excès ayant coutume d'être mauvais, comme aussi afin de me détourner moins du vrai chemin, en cas que je faillisse, que si, ayant choisi l'un des extrêmes, c'eût été l'autre qu'il fallu suivre. (3e partie, para 2)
For indeed when painters themselves wish to represent sirens and satyrs  by means of especially bizarre forms, they surely cannot assign to them utterly new natures. Rather, they simply fuse together the members of various animals. Or if perhaps they concoct something so utterly novel that nothing like it has ever been seen before (and thus is something utterly fictitious and false), yet certainly at the very least the colors from which they fashion it ought to be true. And
For, occupied incessantly with the consideration of the limits prescribed to their power by nature, they [philosophers of former times] became so entirely convinced that nothing was at their disposal except their own thoughts, that this conviction was of itself sufficient to prevent their entertaining any desire of other objects; and over their thoughts they acquired a sway so absolute, that they had some ground on this account for esteeming themselves more rich and more powerful, more free and more happy, than other men who, whatever be the favors heaped on them by nature and fortune, if destitute of this philosophy, can never command the realization of all their desires.
For to be possessed of a vigorous mind is not enough; the prime requisite is rightly to apply it.
Good sense is, of all things among men, the most equally distributed; for every one thinks himself so abundantly provided with it, that those even who are the most difficult to satisfy in everything else, do not usually desire a larger measure of this quality than they already possess. And in this it is not likely that all are mistaken the conviction is rather to be held as testifying that the power of judging aright and of distinguishing truth from error, which is properly what is called good sense or reason, is by nature equal in all men; and that the diversity of our opinions, consequently, does not arise from some being endowed with a larger share of reason than others, but solely from this, that we conduct our thoughts along different ways, and do not fix our attention on the same objects. For to be possessed of a vigorous mind is not enough; the prime requisite is rightly to apply it. The greatest minds, as they are capable of the highest excellences, are open likewise to the greatest aberrations; and those who travel very slowly may yet make far greater progress, provided they keep always to the straight road, than those who, while they run, forsake it.
I am in doubt as to the propriety of making my first meditations in the place above mentioned matter of discourse; for these are so metaphysical, and so uncommon, as not, perhaps, to be acceptable to every one. And yet, that it may be determined whether the foundations that I have laid are sufficiently secure, I find myself in a measure constrained to advert to them. I had long before remarked that, in relation to practice, it is sometimes necessary to adopt, as if above doubt, opinions which we discern to be highly uncertain, as has been already said; but as I then desired to give my attention solely to the search after truth, I thought that a procedure exactly the opposite was called for, and that I ought to reject as absolutely false all opinions in regard to which I could suppose the least ground for doubt, in order to ascertain whether after that there remained aught in my belief that was wholly indubitable. Accordingly, seeing that our senses sometimes deceive us, I was willing to suppose that there existed nothing really such as they presented to us; and because some men err in reasoning, and fall into paralogisms, even on the simplest matters of geometry, I, convinced that I was as open to error as any other, rejected as false all the reasonings I had hitherto taken for demonstrations; and finally, when I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams. But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat; and as I observed that this truth, I think, therefore I am ["cogito ergo sum"], was so certain and of such evidence that no ground of doubt, however extravagant, could be alleged by the sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search
Il est bon de savoir quelque chose des moeurs de divers peuples, afin de juger des notres plus sainement et que nous ne pensions pas que tout ce qui est contre nos modes soit ridicule et contre raison, ainsi qu'ont coutume de faire ceux qui n'ont rien vu; mais lorsqu'on emploie trop de temps à voyager on devient enfin étranger en son pays; et lorsqu'on est trop curieux des choses qui se pratiquaient aux siècles passés, on demeure ordinairement fort ignorant de celles qui se pratiquent en celui-ci.
I think therefore I am
It is thus quite certain that the constitution of the true religion, the ordinances of which are derived from God, must be incomparably superior to that of every other.
[I]t seems to be just as foolish to say, 'I imagine, in order to understand more clearly what I am,' as to say, 'I am now clearly awake and I see something true, but because I do not yet see it clearly enough I shall fall asleep so that my dreams will represent it to me more truly and clearly.
J'ai été nourri aux lettres dès mon enfance, et pour ce qu'on me persuadait que par leur moyen on pouvait acquérir une connaissance claire et assurée de tout ce qui est utile à la vie, j'avais un extrême désir de les apprendre. Mais sitôt que j'eus achevé tout ce cours d'études au bout duquel on a coutume d'être reçu au rang des doctes, je changeai entièrement d'opinion. Car je me trouvais embarassé de tant de doutes et d'erreurs qu'il me semblait n'avoir fait autre profit en tachant de m'instruire, sinon que j'avais découvert de plus en plus mon ignorance. (1ere partie, para 6)
Je pense, donc je suis; English: I think, therefore I am)
One of the first of the considerations that occurred to me was that there is very often less perfection in works composed of several portions, and carried out by the hands of various masters, than in those on which one individual alone has worked. Thus we see that buildings planned and carried out by one architect alone are usually more beautiful and better proportioned than those which many have tried to put in order and improve, making use of old walls which were built with other ends in view.
philosophes qui ont pu autrefois se soustraire de l'empire de la fortune, et, malgré les douleurs et la pauvreté, disputer de la félicité avec leurs dieux. Car s'occupant sans cesse à considérer les bornes qui leur étaient prescrites par la nature, ils se persuadaient si parfaitement que rien n'était en leur pouvoir que leurs pensées, que cela seul était suffisant pour les empêcher d'avoir aucune affection pour d'autres choses; et ils disposaient d'elles si absolument qu'ils avaient en cela quelque raison de s'estimer plus riches, et plus puissants, et plus libres, et plus heureux qu'aucun des autres hommes, qui, n'ayant point cette philosophie, tant favorisés de la nature et de la fortune qu'ils puissent être, ne disposent jamais ainsi de tout ce qu'ils veulent. (partie 3, para 4)
Reading good books is like engaging in conversation with the most cultivated minds of past centuries who had composed them, or rather, taking part in a well-conducted dialogue in which such minds reveal to us only the best of their thoughts.
that we conduct our thoughts along different ways, and do not fix our attention on the same objects.
[...] the diversity of our opinions, consequently, does not arise from some being endowed with a larger share of reason than others, but solely from this, that we conduct our thoughts along different ways, and do not fix our attention on the same objects. For to be possessed of a vigorous mind is not enough; the prime requisite is rightly to apply it. The greatest minds, as they are capable of the highest excellences, are open likewise to the greatest aberrations; and those who travel very slowly may yet make far greater progress, provided they keep always to the straight road, than those who, while they run, forsake it.
The dreams we imagine when we are asleep should not in any way make us doubt the truth of the thoughts we have when we are awake.
there is often not so much perfection in works composed of many pieces and made by the hands of various master craftsmen as there is in those works on which but a single individual has worked.