Meditation II


I.  his existence (PM 36)

A. following method of Meditation I, will reject whatever is doubtful as if it were false

1. Meditation I:  search for foundations.  distinguish two sorts of errors

2. doubt everything until he either finds something certain or knows for certain that nothing is certain

3. Note the analogy with Archimedes's boast

B. will suppose everything he sees is false: 

1. his senses, body, shape, extension, etc. all a figment of his imagination

2. perhaps nothing is certain

C. Objection:  Is he not certain that God exists and instills these thoughts in him?

   Reply:  (q.v.)

1. no reason to think that

2. all these thoughts or ideas may come from himself

3. but then he would have to be something (q.v.)

D. Objection:  but he doubts his senses and body


1. but what follows from that? 

2. does he need them to exist? 

E. Objection:  but he has persuaded himself that there is nothing in the world:  no minds, no bodies.  So hasn't he persuaded himself at the same time that he does not exist?  (36)

   Reply:  in order to persuade himself of something, would have to exist

F. Objection:  but there could be a deceiver – the “evil genius” of Meditation I

Reply:  even if there were some evil being deceiving him, would have to exist to be deceived

G. Conclusion:  "I am, I exist" is necessarily true every time he says or thinks it (37, q.v.)

   (What about at other times?)

II. his nature:  what he is

A. will apply method of doubt to what he formerly believed himself to be

B. believed that he was a man

1. and that a man is a rational animal

2. but what is "rational?" what is "animal?"

C. believed that he is body and soul

1. soul:

a. he can eat, walk, feel, think (Aristotle) (q.v.)

b. he used to attribute these things to the soul as cause:  body alone cannot do these things

c. but what was his soul?  "rarefied air, or fire, or ether” permeating his body (37)

2. body

a. had no doubts:  under the impression that he knew its nature distinctly

b. has shape, is in a place, fills up space so that it excludes every other body, can be perceived, is movable – but not necessarily capable of self-movement

D. but now, supposing this evil "genius" or deceiver, what is he? 

1. Could not be sure of those things he attributed to body

2. turns to those things he attributed to his soul:

a. eating or moving about:  since he has no body, these are fictions

b. nor sense without a body, nor would he really sense those things he seemed to sense

c. thinking alone cannot be separated from him (q.v.)

E. concludes:

1. "I am, I exist.  That much is certain.  But for how long?  As long as I think."

a. it may be that if he were to stop thinking, he would cease to exist

b. N.B. this is a stronger conclusion than the first one he reached, in which he said only that it was true that he exists each time he said or thinks that he exists

2. he is a thing that thinks, a mind, a soul, understanding, or reason (37-38)

F. what else is he? (38)

1. will try to use his imagination (mental images) (q.v.)

2. he’s not a collection of organs, or some rarefied gas, because he can doubt these things

3. but couldn’t he actually be such things without knowing it?  Not going to argue about it now.  (Will return to this in Meditation VI.)

4. he says he knows he exists and this knowledge could not depend on something he’s not sure of and thus does not depend on anything he can imagine (q.v.)

5. imagination involves contemplating the shape of something, so it's as useless as dreaming

G. Concludes: 

1. he is a thing that thinks

2. by "thinks" he means "doubts, understand, affirms, denies, wills, refuses, and also senses and has mental images"

3. even if he is dreaming or being deceived, so that the things he thinks he sees are not real, it’s still true that it’s him who is having these mental images or thoughts and thus exists (38)

H. however, it is difficult for him not to believe that he knows bodily things better than this thing that thinks that is himself yet that he cannot imagine (38-39, 39 q.v.)

III. Wax experiment (39)

A. fire changes all of the sensible properties of piece of wax taken from hive

B. yet he nevertheless thinks that it is the same piece of wax

C. But how can he know this?

1. not by his senses

a. since everything that falls under the senses has changed

b. perhaps the wax was not the color, odor, etc., but only a physical object that is perceived in one way, then another

2. by his imagination?  (q.v.)

a. “But what exactly is it of which I now have a mental image?”

b. if one takes away from the wax everything known by the senses, what seems to remain is something extended, flexible, capable of change

c. but what is it to say that this thing is flexible and changeable? 

1.) Since the wax is capable of “innumerable” shapes, and he cannot survey innumerable shapes in his imagination, it is not by means of his imagination, his ability to have mental images, that he understands this.  (39)

2.) compare this with the Discourse V argument, in which he says that a physical thing cannot respond to infinitely many questions or situations.

d. similarly the extension may change – when the wax is melted, boiled, etc. – and change in more ways than “he can ever encompass with mental images”

3. thus it is not with his imagination but with his mind (a purely mental inspection) that he perceives that the same piece of wax remains (39-40, q.v.)

D. Problem:  (40)

1. although he is trying to consider these things without words, language gets in the way and he is almost deceived by ordinary usage (q.v.)

2. normally, we say that we see that the wax is present, not that we judge it to be present

3. thus it would seem that it is known by eyesight, not by the mind

E. response: (40)

1. looks out the window at people in the street and is just as likely to say that he sees them as to say that he sees the wax

a. but all he sees are hats and coats

b. could be robots underneath

c. he judges there to be men in the street

2. should not derive doubt from the way we use language

3. similarly with the wax:  When did he first know what it is? (q.v.)

a. senses?

b. “common sense”?

c. after study?

d. it is his mind that considers the "naked" wax under its external, sensible properties

F. the Mind

1. insofar as it is his mind that judges that the wax exists from the fact that he sees, feels, or even imagines it, he is more certain that he exists than that the wax does (q.v.)

2. the same conclusion applies to all other external things

3. since external bodies are, strictly speaking, perceived not by the senses or the imagination but by the mind, nothing can be more easily and evidently perceived by him than his mind (41, q.v.)

G. Note that so far, all he has concluded is that his knowledge of the mind is more certain than his knowledge of other things, including his body.  From this alone it does not follow that his mind is separate from his body.


meditation vi


I. Introduction (41)

A.     Descartes begins the sixth Meditation with the question of the existence of material things – remember he had doubted all these

B.     he says that insofar as they constitute the subject of pure mathematics, they can exist

1. in this aspect, he can conceive them clearly and distinctly

2. God has the power to make all that he can clearly and distinctly perceive -- in other words, he can do anything possible

C. from the faculty of imagination, it seems to follow that material things exist

1. for Descartes, the faculty of imagination appears to be the application of his intellectual or cognitive faculty to a body that is before it

2.     to clarify the difference between the imagination and understanding

a. considers the difference between thinking about a 1000-sided figure (chiliagon) and actually trying to imagine one -- and having that image distinct from that of a 10,000-sided figure (myriagon)

b.  imagination requires extra effort beyond that needed for understanding.  E.g., pentagon (41)

3. in addition, he says, the imagination is not essential to him as a thinking being:  hence, it must depend on something else (42)

4. if he were to have a body, the imagination could work by the mind turning to look at things in the body (q.v.)

a. this would explain how the imagination differs from the intellect.

b. since he can think of no other explanation of the faculty of imagination, he argues from this to the conjecture that a material body exists (q.v.)

c. however, he recognizes that this argument establishes that it is only probable that a body exists

D. senses: 

1. imagines things not only as the objects of mathematics, but with colors, sounds, etc., although less distinctly

2. these things seem to have come from the senses

3. will then turn to the senses to see whether they offer any proof of the existence of material things

a. will review the sorts of things he formerly believed to be real on the basis of his senses (42)

b. then assess his reasons for doubting his senses

c. finally, will consider what to believe now

II. What he formerly believed to be real

A. that he had a body; that there were other physical objects; that they could cause pains and pleasures; he felt appetites and emotions; had sensations of external world, etc.

B. the fact that the ideas of these external bodies came to him independently of his desires gave him some reason to think that these sensations came from external objects that were different from his thought (42-43, q.v.)

1. cannot have a sensation of an object no matter how hard we wish if it is not before our sense organs (43)

2. nor can we help seeing it if it is there

3. ideas of sensation more lively, explicit, distinct than ideas from imagination or memory

C. since he had no knowledge of these objects other than from his ideas, he assumed that these objects must resemble his ideas

D. convinced himself that there was nothing he understood that had not come from his senses

1. had use of senses before his reason

2. ideas of imagination less explicit than those of sensation and were constructed from parts taken from sensation (43)

E. finally, he concluded that his body really belonged to him more than any other body

1. feels the appetites and emotions that are in his body

2. yet could not explain the effects these things – pains, hunger, etc. – had on his mind, other than to say that nature taught him so (q.v.)

III. Reasons for doubting his senses

A. certain particular experiences

1. confusing round with square towers

2. mistaking size of statues

3. hearing of amputees who felt pains in missing limbs

B. reasons of general application:

1. If sensations in dreams do not come from external objects, what reason do we have to believe that those in our waking life do?

2. until he had established existence of God, there was the possibility of his being deceived

C.     arguments for truth of what senses teach him were not convincing (44)

1.     that he was taught by nature did not convince him, since sometimes nature and reason pushed him in opposite directions (44, q.v.)

2.     even the fact that sensations come to him independently of his will does not prove that they come from external objects -- may come from some unknown faculty

IV. What to believe now

A. now that he knows himself and God better, no reason to either believe everything his senses tell him, nor to reject everything they tell him

B. the mind-body distinction:

1. whatever he can clearly and distinctly understand apart from another thing God can actually make separate (q.v.)

2. from the fact that he clearly and distinctly conceives himself as a thinking being distinct from body it follows that he really is distinct from his body and could exist without it (q.v.)

C. the existence of material things

1. in order to demonstrate the existence of material things from the fact that he perceives them, Descartes first finds it necessary to draw some distinctions concerning his faculty of perception

2. first says that imagining and sensing are modes of thought or awareness (44)

a.     that is, that his mind can exist without them, but that they cannot exist without some mind (q.v.)

b.     just as, for example, changing place or taking on shapes are modes of body

3. then Descartes distinguishes the passive ability to sense ideas from the active power of producing them

a.     passive ability is in him

b.     but active power cannot be in him (q.v.)

1.) does not presuppose his thought

2.) independent of and sometimes opposed to his will

4. so this active faculty of producing ideas must exist in some other substance, which contains all the reality in these ideas either formally or eminently (44-45)

a. either a physical object (45)

b. or God or some other higher creature

5. can't be God

a. since he is no deceiver, he does not send us ideas of physical world directly or even indirectly through some other creature

b. note:  when he says that God is not a deceiver, Descartes is not claiming that he never makes mistakes.  What he says is that God would not allow him to have any false opinions for which he did not have the ability to correct (45, q.v.)

6. so physical objects must exist

a. they are perhaps not exactly as we see them, as much of our perception is obscure and confused

b. nevertheless, all that we clearly and distinctly conceive in them exists, that is, all the properties of physical objects that fall within the scope of mathematics (q.v.)

D.     even in the things which are either particular, such as size or shape of the sun, or not clearly and distinctly perceived there is some truth

1.     again, God is not a deceiver

2.     he has not permitted Descartes to make any errors that he does not have the faculty to correct

E. similarly, there is at least some truth in those things which are taught to him by nature

1. by nature, means

a. God himself

b. or, the order He has established in the created world

c. or, with reference to Descartes’s own nature, he means all that God has given him (45)

2. among the things that are taught to him by nature that seem to him to be true:

a.     he has a body that is injured when he feels pain, that needs food when he feels hungry, drink when he feels thirsty

b.     that he is present in his body not merely as a sailor is in a ship

c. things like hunger, thirst, pain, are “confused” modifications of thought, resulting from union of mind and body

d. that there are other bodies out there besides his own

e. that his perceptions of the colors, sounds, odors, flavors, etc. of these bodies correspond to real differences in them such that the appealing ones are good for him and the unappealing ones are bad for him (45-46)

V.  Problem of Error (46)

A. however, nature also seems to teach him things that are not so

B. examples:

1. that space in which there is nothing that affects his senses is empty

2. that qualities such as heat, color, and taste are in bodies

3. that distant objects are the size that they appear to us (46)

C. must clarify how he’s using “taught by nature”

1.     by nature, he now means not everything that God has given him, but only that which He has given him insofar as he is a combination of mind and body

2. nature in this sense teaches him to avoid things that cause pain and seek those that give pleasure (q.v.)

a. it does not teach us to conclude anything about external things without first making an inquiry

b. it is the job of the mind to try to reach the truth about such things

c. it is the job of perception, which involves both mind and body, to tell him what is beneficial and what is harmful for his mind and body (q.v.)

D. Objection: even in the case of judging what is good or bad for us, we sometimes make mistakes, such as eating poisoned food (47)

E. Reply:

1. we are attracted by the food, not the poison

2. we are not omniscient:  we do not always know when food is poisoned

F. Objection continued:

1. sometimes nature impels us directly to things that are bad for us (47) 

2. 2nd example:  person with dropsy who is impelled to drink

3. one might say that in sick people, their nature is corrupted 

a. but sick people are just as much God's creatures as healthy people are

b. so why should God let their nature deceive them?  Why should people with dropsy feel thirsty at a time when drink would be bad for them?

G. Descartes's reply:

1.     distinguishes two senses of the word "nature" by making an analogy between people and clocks

2.     in the first sense, "nature" is something that is really in things

a. even a poorly made clock that does not keep proper time runs according to the laws of nature

b. similarly, it is in accordance with nature for the dropsical person to feel thirsty, just as much as it is for a healthy person

3.     in the second sense, "nature" is an extrinsic designation that depends on one's thinking.  It is only in this second sense that we say that an inaccurate clock or the dropsical patient deviates from nature or that his nature is corrupted (47, q.v.)

H. Objection continued: 

1. Nevertheless, it is still a real error for the dropsical patient to feel thirsty

2. must inquire as to why God does not prevent this

I. Descartes's reply:  (48)

1. body is divisible, mind is indivisible

a. mind has no parts

b. losing part of the body does not affect the mind

c. abilities to will, sense, understand are not parts, since it’s one and the same mind that does all these things

d. this alone could prove the difference between mind and body, if he had not already done so

2. mind does not receive impressions from the whole body but only from one small part of the brain:  the common sense (N.B.:  The Cartesian theater)

3. whenever the common sense is affected in the same way, it gives rise to the same perception in the mind, regardless how the rest of the body is arranged

4. also, body is such that in whatever way a part of it could be moved by the movement of a distant part, it could also be moved by the movement of an intermediate part (48)

a. compares nerves to strings, which will produce the same effect no matter where along their entire length they are pulled

b. example:  may feel a pain in the foot from a pinched nerve in the neck even when the foot is not hurt

5. since only one kind of sensation can be produced by a motion in the part of the brain that is directly connected with the mind, it is best that it produce that kind of sensation that is most conducive to a healthy person (q.v.)

a. that the nerve from the foot tells us there's something wrong with the foot

b. or, when we are in need of liquid, that the dryness in throat moves a nerve that moves the parts of the brain that affects the mind as thirst (49)

6. hence, even though God is good, since human beings are composed of mind and body, they will sometimes be deceived

7. in the case of dropsy, dryness in the throat produces a sensation of thirst because in the majority of cases that is the most useful thing for us to know (q.v.)

VI. Conclusion (49)

A. recognizing, avoiding and correcting errors

1. all of the senses show him what is true more often than what is false

2. he can often use several of his senses along with his memory and his understanding of the causes of his errors in order to correct them

B. hence, he need not fear that what is daily presented to his senses is false

1. he can thus remove the exaggerated doubt with which he began these meditations

2. in particular, he can reject the idea that there is nothing to separate waking and dreaming

a.     memory cannot connect dreams with each other and the course of ordinary life the way it does when he is awake

b.     if, when he puts together memory, understanding, and the senses, none of them find anything to correct in the other, then what he thinks is true, again because God is no deceiver

3. we make mistakes because sometimes we must act before we have time carefully to examine our opinions (49-50)



Objections and Replies


Mersenne’s objections:  (50)

I.      Doubting physical things was just a fiction

II.    how does Descartes really know that this thinking thing that he is is not in fact body?

III.  How can Descartes prove that body cannot think?


Descartes’s Reply


I.  by the end of the Second Meditation, he had not yet proved that the mind is in fact distinct from the body, but only that the mind was better known (50-51, q.v.)

II. It’s in the Sixth Meditation where he proves that the body is incapable of thinking (51-52)

A. quotes passage we already discussed on p. 44 (with some variation), to the effect that his idea of mind is clear and distinct from that of body (52, q.v.)

B. asks how else one could know that two things are distinct (q.v.)

1. by the senses?

a. but these are not reliable

b. anyway, he showed in the Second Meditation that things are not really perceived by the senses but by the intellect

2. and we cannot perceive that one thing is apart from another unless we have clear and distinct ideas, which brings us back to Descartes’s original argument

Arnauld’s Objection (53)

N.B. not labeled as such in text


I.  How does it follow from the fact that Descartes is aware of nothing else belonging to his essence that nothing else in fact does belong?

II. He then quotes the argument from the Sixth Meditation (p. 44) again and analyzes it

A. he grants Descartes the “major premiss

1. that is, whatever he can clearly and distinctly understand as separate God could make that way

2. but Arnauld argues that this applies only to our knowledge that is “adequate”

B. he then questions Descartes’s “minor premiss,” that is, he questions whether Descartes actually has adequate conceptions of mind and body

1. with respect to Descartes’s idea of body, it’s not good enough for him to say that he has a complete conception of it when he says it has extension, shape, motion, etc., and that it includes nothing of the nature of a mind, since nobody is claiming that all bodies have minds (53-54, q.v.)

a. body could be related to mind as genus to species

b. it’s possible to have a complete understanding of the genus separate from the species, even if we deny of the genus what is true of the species – negation of species does not imply negation of genus

2. and Descartes nowhere provides an argument that the mind can be completely understood without body (54)

a. Descartes’s argument that he can doubt his body without doubting his mind only shows that he can have some knowledge of himself without having knowledge of his body

b. but it does not show that this knowledge is complete and adequate

C. to illustrate his point, Arnauld uses the example of a triangle inscribed in a semi-circle

1. Suppose someone knew that the inscribed triangle was a right triangle, but doubted that the square of the hypotenuse equaled the sum of the squares of the other two sides

2. it doesn’t follow that God could create a right triangle that didn’t agree with the Pythagorean theorem (54-55)

3. the only possibility is that the man in question did not really have an adequate knowledge of right triangles (55)

D. so, in the same way, Descartes could have inadequate knowledge of himself as a thinking thing

E. Also makes an analogy with the way in which geometry conceives of lines without breadth, etc.  that is, although one can mentally abstract length from breadth, it can’t exist without it.  Same for thought and body.


Descartes Replies Again (56)

(also not labeled)


I.  Denies that body could be related to mind as genus to species, since species cannot be understood without their genus

A. but mind can be completely and distinctly understood without any of the properties by which we recognize bodies

B. his critic says that this knowledge Descartes has of himself is not complete and adequate, using the example of the triangle to illustrate his point

C. But Descartes thinks the triangle example is different from the mind case in three ways:

1. even if one thought of the triangle as a triangular substance, the square of the hypotenuse is not a substance, so neither the triangle nor the square can be thought of as a complete “thing” in the way that the mind and body can

   -- this appears to me to beg the question:  the whole point of the line without breadth analogy is to call into question whether the mind really is a thing

2. second argument is at least more clear: (56-57)

a. although we could know a triangle is right-angled without knowing its Pythagorean property, we couldn’t know the latter without the former

b. but we can clearly and distinctly perceive the body without the mind and the mind without the body (57)

   -- again, this appears to be assuming what he needs to prove

3. third difference:  (57)

a. although someone may not know that the square of the hypotenuse is equal to the sum of squares of the two sides, he at least knows that there must be some ratio.  It’s not possible to have a concept of triangle otherwise

b. but the concepts of mind and body include nothing of each other

   -- perhaps true, but this is about the concepts of mind and body, not about the mind and body themselves

4. Descartes is really struggling to answer Arnauld here

II. then argues that the mere fact that he can clearly and distinctly understand one substance apart from another, it follows that they really are different

A. “substance” means something that exists by itself, without the aid of any other substance

B. if there are two different concepts of two substances then they really are distinct

C. hence, he had actually shown that the mind and body are distinct by the end of the Second Meditation, and only went into all the stuff about God and truth in order to remove the exaggerated doubts of the First Meditation, where he had doubted even God (57-58)

D. the mind and body case is unlike Arnauld’s triangle example, because it is possible to deny the properties of body to the mind, but not the Pythagorean property of right triangles (58)

E. Again, Descartes is talking about our concepts of mind and body again, assuming that these different concepts agree with what we find in reality, an assumption that depends on God’s truthfulness