Descartes: Discourse On Method Quotes

On The External Control Of Our Environments:
I considered how one and the same man with the very same mind, were he brought up from infancy among the French or the Germans, would become different from what he would be had he always lived among the Chinese or the cannibals, and how, even down to the styles of our clothing, the same thing that pleased us ten years ago, and that perhaps will again please us ten years hence, now seems to us extravagant and ridiculous.  … Hence I [chose to be] constrained to try to guide myself on my own.
(Discourse On Method, Part II, page 9-10)

The Method:
[Just as law is best kept dramatically parsimonous and rigidly enforced, so these principles]:
1) The first [principle] was to never accept anything as true that I did not plainly know to be such; that is to say, carefully to avoid hasty judgment than what presented itself to my mind so clearly and so distinctly that I had no occasion to call it in doubt.
2) The second [principle], to divide each of the difficulties I would examine into as many parts as possible, and as was required, in order better to resolve them.
3) The third [principle], to conduct my thoughts in an orderly fashion, by commencing with those objects that are simplest and easiest to know, in order to ascend little by little, as by degrees, to the knowledge of the most composite things…
4) And the last [principle], everywhere to make enumerations so complete and reviews so general that I was assured of having omitted nothing.
(Discourse On Method, Part II, page 11)

On Deriving Context From Graphical Models:
I thought it would be more worthwhile for me to examine only these [mathematical concepts] in general, and to suppose them only in subject that would help me make the knowledge of them easier…. Then, having noted that, in order to know these [concepts], I would sometimes need to consider each of them individually, and sometimes only to keep them in mind, or to grasp many of them together, I thought that, in order better to consider them in particular, I ought to suppose them to be relations between lines, since I found nothing more simple, or nothing that I could represent more distinctly to my imagination and to my senses; but that, in order to keep them in mind or to grasp many of them together, I would have to explicate them by means of certain symbols, the briefest ones possible; and that by this means I would be borrowing all that is best in geometrical analysis and algebra, and correcting all the defects of the one by the other.
(Discourse On Method, Part III, page 12)

On The Distinction Between Reason And Empiricism:
Everything unimaginable [to the senses] seems to [many people] unintelligible.  Even philosophers take it as a maxim in the schools that there is nothing in the understanding that has not first been in the senses, where it is nevertheless certain that the ideas of God and the soul have never been.  And it seems to me that those who want to use their imagination to grasp these ideas are doing the very same thing as if, in order to hear sounds or to smell odors, they wanted to use their eyes.
(Discourse On Method, Part IV, page 21)

On The Certainty Of Metaphysics Over The Sciences:
Finally, if there still are men who have not been sufficiently persuaded of the existence of God and of their soul by means of the reasons I have brought forward, I very much want them to know that all the other things of which they think themselves perhaps more assured, such as having a body, that there are stars and an earth, and the like, are less certain.
(Discourse On Method, Part IV, page 21)

On Truth Originating From Divine Clarity:
It follows from [divine perfection] that our ideas or notions, being real things and coming from God, cannot, in all that is clear and distinct in them, be anything but true.  Thus, if we quite often have ideas that contain some falsity, this can only be the case with respect to things that have something confused or obscure about them, because in this respect they participate in nothing; that is, they are thus confused in us only because we are not perfect…. But if we did not know that all that is real and true in us comes from a perfect and infinite being – however clear and distinct our ideas were, we would have no reason that assured us that they had the perfection of being true.  
(Discourse On Method, Part IV, page 22)

On Philosophical Zombies:
I contented myself with supposing that God formed the body of a man exactly like one of ours, as much in the outward shape of its members as in the internal arrangement of its organs… without putting into it, at the start, any rational soul, or anything else to serve there as a vegetative or sensitive soul, but merely kindled in the man’s heart one of those fires without light….  For on examining the functions that could, as a consequence, be in this body, I found there precisely all those things that can be in us without our thinking about them, and hence, without our soul’s contributing to them….  And these are all the same features in which one can say that animals lacking reason resemble us.
(Discourse On Method, Part V, page 26)

[While this is not the case for animals], if there were any such machines that bore a resemblance to our bodies and imitated our actions as far as this is practically feasible, we would always have two very certain means of recognizing that they were not at all true men.  The first is that they could never use words or other signs, or put them together as we do in order to declare our thoughts to others.  For one can well conceive of a machine that utters words, and even that utters words appropriate to the bodily actions that will cause some change in its organs….  But it could not arrange its words differently so as to respond to the sense of all that will be said in its presence, as even the dullest man can do.  The second means is that, although they might perform many tasks very well or perhaps better than any of us, such machines would invitably fail in other tasks; by this means one would discover that they were acting not through knowledge but only through the disposition of their organs.  For while reason is universal… these organs require some particular disposition for each particular action; consequently, it is for all practical purposes impossible for there to be enough different organs in a machine to make it act in all the contingencies of life in the same way as our reason makes us act.  
(Discourse On Method, Part VI, page 32)

On The Purpose Of The Lungs:
The true function of respiration is to bring enough fresh air into the lungs to cause the blood which comes there from the right cavity of the heart, where it has been rarified and, as it were, changed into vapors, immediately to be condensed and to be converted once again into blood before returning to the left cavity; without this process the blood could not properly aid in feeding the fire that is in the heart.
(Discourse On Method, Part V, page 30)
[Note: this was, of course, ultimately proved incorrect]

On Immortality Of The Soul:
When one knows how different [soul and body] are, one understands much better the arguments which prove that our soul is of a nature entirely independent of the body, and consequently that it is not subject to die with it.  Then, since we do not see any other causes at all for its destruction, we are naturally led to judge from this that it is immortal.  
(Discourse On Method, Part VI, page 33)

On The Inferiority Of A-T Philosophy Against Science:
It is possible to arrive at knowledge that would be very useful in life and that, in place of that speculative philosophy taught in the schools , it is possible to find a practical philosophy, by means of which, knowing the force and the actions of fire, water, air, the stars, the heavens, and all the other bodies that surround us, just as distinctly as we know the various skills of our craftsmen, we might be able, in the same way, to use them for all the purposes for which they are appropriate, and thus render ourselves, as it were, masters and possessors of nature… perhaps even [rid oneself] of the frailty of old age…
(Discourse On Method, Part VI, page 35)
[Note: “philosophy taught in the schools” is likely directed at A-T scholasticism]

I am sure that that the most impassioned of those who now follow Aristotle would believe themselves fortunate, if they had as much knowledge of nature as he had, even if it were on the condition that they would never have any more.  They are like ivy, which never stretches any higher than the trees supporting it, and which often even descends again after if has reached their tops, for it seems to me that they are re-descending, that is, they are making themselves somehow less knowledgeable than if they abstained from studying; not content with knowing all that is intelligibly explained in their author, they want in addition to find the solutions there to many difficulties about which he says nothing and about which he has perhaps never thought.  Still, their manner of philosophizing is very convenient for those who have only very mediocre minds, for the obscurity of the distinctions and the principles they make use of is the reason why they can speak about all things as boldly as if they knew them, and why they can uphold everything they say against the most subtle and the most adroit, without anyone’s having the means of convincing them they are mistaken.  In this they seem to me like a blind man who, in order to fight without a disadvantage against someone who is sighted, had made his opponent go into the depths of some very dark cellar.  
(Discourse On Method, Part VI, page 40)

On His Aspirations For Inspiring Post-Mortem Audiences:
I [published] as much to have all the more occasion to examine [my judgments] well (since without doubt one always looks more carefully at what one believes must be seen by many, than at what one does only for oneself; and often the things that have seemed to me to be true when I began to conceive them have appeared false to me when I wanted to put them on paper), as in order not to lose any occasion to benefit the public, if I am able, and in order that, if my writings are worth anything, those who will have them after my death can thus use them as will be most fitting.
(Discourse On Method, Part VI, page 37)

On Reasons For Self-Censorship After Galileo:
I would have many opportunities to lose time, had I published the foundations of my physics.  For although they are nearly all so evident that it is necessary only to understand them in order to believe them, and although there has not been a single one for which I did not believe I could give demonstrations, nevertheless, because it is impossible for them to be in agreement with all the diverse opinions of other men, I foresee that I would often be distracted by the disputes they would engender.
(Discourse On Method, Part VI, page 38)

On The Disadvantages Of Social Learning:
In this way, if there were someone in the world whom one assuredly knows to be capable of finding the greatest things and the things as beneficial to the public as possible and whom, for this cause, other men were to exert themselves to help in every way to succeed in his plans, I do not see that they could do a thing for him except to make a donation toward the expenses of the experiments he would need and, for the rest, to prevent his leisure from being wasted by the importunity of anyone.
(Discourse On Method, Part VI, page 41)

On Experience Being The Groundwork Of Semantic Webs:
The reasonings [in my essay presenting a considerable number of scientific results] follow each other in such a way, just as the last are demonstrated by means of the first, which are their causes, so these first are reciprocally demonstrated by means of the last, which are their effects.  And one must not imagine that I am here committing the fallacy that logicians call a circle, for, experience rendering the majority of these effects very certain, the causes from which I deduce these effects serve not so much to prove them as to explain them; on the contrary, it is rather the case that the causes are what are proved by the effects.
(Discourse On Method, Part VI, page 43)

Descartes: Meditations On First Philosophy Quotes

On Why He Couldn’t Assert Immortality Of The Soul Immediately:
But because some people will perhaps expect to see proofs for the immortality of the soul in this [second] Meditation, I think they should put on notice here that I have attempted to write only what I have carefully demonstrated…….
(Meditations On First Philosophy, Synopsis, page 54)
[Note: Descartes has to spend a lot of time placating the crazies]

On The Relation Between Philosophy And Theology:
I have always thought that two issues – namely, God and the soul – are chief among those that ought to be demonstrated with the aid of philosophy rather than theology.
(Meditations On First Philosophy, Dedication, page 47)

On Atheism:
Granted, it is altogether true that we must believe in God’s existence because it is taught in the Holy scriptures, and, conversely, that we must believe the Holy Scriptures because they have come from God. This is because, of course, since faith is a gift from God, the very same one who gives the grace that is necessary for believing the rest can also give the grace to believe that he exists. Nonetheless, this reasoning cannot be proposed to unbelievers because they would judge it to be circular.
(Meditations On First Philosophy, Dedication, page 47)

Moreover, I know that there are many irreligious people who refuse to believe that God exists and that the human mind is distinct from the body – for no other reason than their claim that up until now no one has been able to demonstrate these two things.
(Meditations On First Philosophy, Dedication, page 48)

I have seen two rather lengthy treatises [that respond to Discourse On Method], but these works, utilizing as they do arguments drawn from atheist commonplaces, focused their attack not so much on my arguments regarding these issues, as on my conclusions. Moreover, arguments of this type exercise no influence over those who understand my arguments, and the judgments of many people are so preposterous and feeble that they are more likely to be persuaded by the first opinions to come along, however false and contrary to reason they may be, than by a true and firm refutation of them which they hear subsequently. Accordingly, I have no desire to respond here to these objections, lest I first have to state what they are. I will only say in general that all the objections typically bandied about by the atheists to assail the existence of God always depend either on ascribing human emotions to God, or on arrogantly claiming for our minds such power and wisdom that we attempt to determine and grasp fully what God can and ought to do. Hence these objections will cause us no difficulty, provided we but remember that our minds are to be regarded as finite, while God is to be regarded as incomprehensible and infinite.
(Meditations On First Philosophy, Preface, page 52)

On The Certainty Of His Meditations And Their Potential For Misinterpretations:
Although the arguments I use here do, in my opinion, equal or even surpass those of geometry in certitude and obviousness, nevertheless I am fearful that many people will not be capable of adequately perceiving them, both because they are a bit lengthy, with some of them depending on still others, and also because… they demand a mind quite free from prejudices and that can easily withdraw itself from association of the senses. Certainly there are not to be found in the world more people with an aptitude for metaphysical studies than those with an aptitude for geometry.
(Meditations On First Philosophy, Dedication, page 49)

On Teleology:
…the entire class of causes which people customarily derive from a thing’s “end,” I judge to be utterly useless in physics. It is not without rashness that I think myself capable of inquiring into the ends of God.
(Meditations On First Philosophy, Meditation 4, page 82)

On Truth And Clarity And Certainty:
I am certain that I am a thinking thing. But do I not therefore also know what is required for me to be certain of anything? Surely in this first instance of knowledge, there is nothing but a certain clear and distinct perception of what I affirm. Yet this would hardly be enough to render me certain of the truth of a thing, if it could ever happen that something that I perceived so clearly and distinctly were false. And thus I now seem able to posit as a general rule that everything I very clearly and distinctly perceive is true.
(Meditations On First Philosophy, Meditation 3, page 70)

[The idea of God discloses to me something real… it is] an idea that is utterly clear and distinct… for whatever I clearly and distinctly perceive to be real and true and to involve some perfection is wholly contained in that idea.
(Meditations On First Philosophy, Meditation 3, page 77)

But once I perceived that there is a God, and also understood at the same time that everything else depends on him, and that he is not a deceiver, I then concluded that everything that I clearly and distinctly perceive to be true. Hence even if I no longer attend to the reasoning leading me to judge this to be true, so long as I merely recall that I did clearly and distinctly observe it, no counter-argument can be brought forward that might force me to doubt it. On the contrary, I have a true and certain knowledge of it. … For what objections can now be raised against me? That I have been made such that I am often mistaken? But I now know that I cannot be mistaken in matters I plainly understand. That I have taken many things to be true and certain which subsequently I recognized to be false? But none of these were things I clearly and distinctly perceived. But I was ignorant of this rule for determining the truth, and I believed these things perhaps for other reasons which I later discovered were less firm.
(Meditations On First Philosophy, Meditation 5, page 92)
[Note: Notice how God’s existence ties in (precedes?) this understanding of truth as clarity.]

On God’s Existence:
In fact the idea I clearly have of the human mind – insofar as it is a thinking thing, not extended in length, breadth or depth, and having nothing else from the body – is far more distinct than the idea of any corporeal thing. And when I take note of the fact that I doubt, or that I am a thing that is incomplete and dependent, there comes to mind a clear and distinct idea of a being that is independent and complete, that is, an idea of God. And from the mere fact that such an idea is in me, or that I who have this idea exist, I draw the obvious conclusion that God also exists, and that my existence depends entirely upon him at each and every moment. This conclusion is so obvious that I am confident that the human mind can know nothing more evident or more certain.
(Meditations On First Philosophy, Meditation 4, page 81)

However, as far as God is concerned, if I were not overwhelmed by prejudices and if the images of sensible things were not besieging my thought from all directions, I would certainly acknowledge nothing sooner or more easily than [God].
(Meditations On First Philosophy, Meditation 5, page 91).

For just as the objective mode of being belongs to ideas by their very nature, so the normal mode of being belongs to the causes of ideas, at least to the first and preeminent ones, by their very nature. And although one idea can perhaps issue from another, nevertheless no infinite regress is permitted here; eventually some first idea must be reached whose cause is a sort of archetype that contains formally all the reality that is in the idea merely objectively.
(Meditations On First Philosophy, Meditation 3, page 74)

On Why One Can Invent Corporeal Ideas, But Not Divine Ideas:
As to the ideas of corporeal things, there is nothing in them that is so great that it seems incapable of having originated from me… There is another kind of falsity (called “material” falsity) which is found in ideas whenever they represent a non-thing as if it were a thing… Assuredly I need not assign to these ideas an author distinct from myself. For if they were false, that is, if they were to represent non-things, I know by the light of nature that they proceed from nothing; that is, they are in me for no other reason that something is lacking in my nature. If, on the other hand, these ideas are true, then because they exhibit so little reality to me that I cannot distinguish it from a non-thing, I see no reason why they cannot get their being from me.
(Meditations On First Philosophy, Meditation 3, page 75

On “The Unicorn Defense”:
From the fact that I think of God as existing, it does not seem to follow that God exists, for my thought imposes no necessity on things. And just as one may image a winged horse, without there being a horse that has wings, in the same way perhaps I can attach existence to God, even though no God exists. But there is a sophism lurking here. From the fact that I am unable to think of a mountain without a valley, it does not follow that a mountain or a valley exists anywhere, but only that, whether they exist or not, a mountain and a valley are inseparable from one another. But from the fact that I cannot think of God except as existing, it follows that existence is inseparable from God, and that for this reason he really exists.
(Meditations On First Philosophy, Meditation 5, page 89)

On The Unreliability Of The Senses:
Many experiences gradually weakened any faith that I had in the senses… [examples include phantom limb pain and flaws in visual recognition]… To these causes for doubt I recently added two quite general ones. The first was that everything I ever thought I sensed while awake I could believe I also sometimes sensed while asleep, and since I do not believe that what I seem to sense in my dreams comes to me from things external to me, I saw no reason why I should hold this belief about those things I seem to be sensing while awake. The second was that, since I was ignorant of the author of my origin (or at least pretended to be ignorant of it), I saw nothing to prevent my having been so constituted by nature that I should be mistaken even about what seemed to me most true.
(Meditations On First Philosophy, Meditation 6, page 95)

Thus what I thought I had seen with my eyes, I actually grasped solely with the faculty of judgment, which is in my mind.
(Meditations On First Philosophy, Meditation 2, page 68)

On Why “Everything That Begins To Exist Has A Cause” Includes The Non-Corporeal:
Now it is indeed evident by the light of nature that there must be at least as much [reality] in the efficient and total cause as there is in the effect of that same cause. For whence, I ask, could an effect get its reality, if not from a cause? And how could the cause give that reality to the effect, unless it also possessed that reality? Hence it follows that something cannot come into being out of nothing, and also that what is more perfect (that is, what contains in itself more reality) cannot come into being from what is less perfect. But this is manifestly true not merely for those effects whose reality is actual or formal, but also for ideas in which only objective reality is considered… As imperfect a mode of being as this is by which a thing exists in the intellect objectively through an idea, nevertheless it is plainly not nothing, hence it cannot get its being from nothing.
(Meditations On First Philosophy, Meditation 3, page 73-74)

On Thought And Forms:
Rather, the very nature of an idea is such that of itself it needs no formal reality other than what it borrows from my thought, of which it is a mode.
(Meditations On First Philosophy, Meditation 3, page 76)

I am a substance.
(Meditations On First Philosophy, Meditation 3, page 76)

On Self-Knowledge Never Being Wrong:
Now as far as ideas are concerned, if they are considered alone and in their own right, without being referred to something else, they cannot, properly speaking, be false. For whether it is a she-goat or a chimera that I am imagining, it is no less true that I imagine the one than the other. Moreover, we need not fear that there is falsity in the will itself or in the affects, for although I can choose evil things or even things that are utterly non-existent, I cannot conclude that it is untrue that I do choose these things. Thus there remain only judgments in which I must take care not to be mistaken.
(Meditations On First Philosophy, Meditation 3, page 71)
[Note: Above passage seems to hint at an is-ought distinction.]