Philosophy of Dreams and Sleeping:
Renaissance and Early Modern
Philosophy views
Markku Roinila
Renaissance philosophy of dreams
 Most Renaissance
philosophers followed more
or less the Ancient views,
especially Aristotle and the
medical accounts of sleep.
 Marsilio Ficino’s neoplatonist
philosophy // sleep does not
affect the highest spiritual
part of the soul – this was a
popular view from many of
thinkers in the occultist
natural philosophy from
Paracelcus to Fludd.
Ficino on the higher spheres
“If this is so, why should not also the higher minds
that are conjunct with our mind always move it? We
are not aware of this impulse when our middle part
is so much occupied with its own acts that the
influence of the mind does not reach it. But when it
is empty, what would stop some angelic thinking
from entering our rational powers, although we
cannot see where it comes from? This is evident in
those who, without a teacher, only by the intention
of emptied reason or even in a calm state, have
often discovered many outstanding things even
without looking for them, as though the light of the
sun were suddenly and spontaneously diffused
through the serene air.” (Ficino, Theologia Platonica
XIII.2
 According to Ficino, the highest soul can be in
contact with higher spheres and be informed by
them when lower levels do not interfere; such
cases can occur during sleep.
Paracelcus
“Thus nothing is idle in nature. All things are at
work from hour to hour, from day to day, from
night to night. Only human beings rest at night
and do not work at Sabbath because of the divine
command. But the day of rest has not been
ordained for the spirit which must not be idle and
rest; it is established only for the rest of the body,
as of the beasts of the field and whatever pertains
to it. The spirit must always be at work, and
neither sleep nor Sabbath can make it still and
quiet. The same goes for all creatures. Even
though their body rests, their spirit never stands
still and continues to work each day.” (Paracelsus,
Werke I.13)
 The idea of spiritual progress in sleep, when
the disturbing external effects are excluded,
fascinates Paracelsus and other authors who
combine mysticism with natural philosophy.
This view is unique to Renaissance thinkers
and have no predecessors in Ancient or
Medieval tradition.
Early Modern Philosophy of Dreams
 A general theme in Early Modern
philosophy (around Descartes to Kant)
is appearance vs. reality: can we
perceive the world as it is? What is real
and what is illusion? This was reflected
in the philosophy of dreams, although
the continuation to Ancient and
Medieval tradition is clear. Early
modernists were interested in
perception, the knowledge of reality.
All agreed that dreams are perceptual.
 Secularization, trying to find natural
causes for dreams instead of relying to
divination-explanations
 Nevertheless, the Early Modern period
is perhaps the foremost period in the
history of philosophy when dreams
were discussed. The discussion was
started by René Descartes and the
other philosophers continued the
discussion.
Central themes in
Early Modern Philosophy of Dreams
 General division between rationalists (we can have knowledge without
sense experience) vs. empiricistst (sense experience is necessary in
order to gain knowledge).
 Is there cognitive activity in sleep? This is a continuation from Aristotle.
Descartes argued that the soul always thinks, but many empiricists
thought this was absurd.
 How can we know that our perceptual experiences are not dreams and
the reality is not mere dream? (dream-scepticism) This problem was
raised already by Plato, but made popular again by Descartes in his
Meditations.
 What causes the content of dreams? Most thought that they follow
naturally from the physical and mental states of the organism. This
means that divination as the Stoics had it disappears from the dream
theories. Some Early Moderns (Hobbes, for example) discussed on the
effects of external stimuli to the dreams.
Descartes on dreams
 René Descartes (1596-1650) was the
most important and the most
controversial philosopher on dreams in
the Early Modern philosophy and
probably of all time.
 He continued the Ancient tradition, but
combined with the Ancient views the
idea of dreams as perceptions and the
idea of appareance vs. reality.
 Descartes established dream scepticism,
perhaps the most well-known argument
concerning dreams (compare, for
example, the film Matrix).
 There are discussion of dreams in most
central philosophical works of
Descartes: Discourse on Method,
Meditations on the First Philosophy and
Principles of Philosophy.
The soul is always thinking
 One of Descartes’ most controversial claims is that the soul is always thinking,
even in sleep.
”The reason why I believe that the soul is always thinking is the same that makes
me believe that light is always shining even though there are no eyes looking at it,
that heat is always warm even though it heats no one, that the matter or extended
substance always has extension, and in general, that what constitutes the nature of
a thing always belongs to it as long as it exists. Therefore it would be easier for me
to believe that the soul ceases to exist when it is said to cease thinking than to
conceive that it exists without thought. And I see no difficulty here, unless it is
regarded as superfluous to believe that it thinks in case no memory of it remains in
us afterwards. But if we consider that every night we have a thousand thoughts, and
even awake a thousand thoughts in an hour, which leave no more trace in our
memory and seem no more useful than the thoughts we may have had before our
birth, it is easier to be convinced of this than to judge that a substance whose
nature is to think can exist without thinking.” (Descartes, Letter to Gibieuf, 19
January 1642, AT III, 479)
Objections
 Gassendi thought the claim absurd in his objections to Descartes’s Meditations, but D.
defended himself as follows: ”‘You say you want to stop and ask whether I assume the soul
always thinks. But why should it not always think, when it is a thinking substance? Is it so
strange that we do not remember the thoughts that the soul had in mother’s womb or in
deep sleep?”
 This claim puzzled the followers of Descartes. For example, Arnauld asked if it would not be
enough that the soul preserves its ability to think at every moment, but Descartes
emphasized that actual thought is necessary (Letter 4 June 1648, AT V, 193).
 Locke’s ridicule: “Who can find it reasonable, that the Soul should, in its retirement, during
sleep, have so many hours thoughts, and yet never light on any of those Ideas it borrowed not
from Sensation or Reflection, or at least preserve the memory of none, but such, which being
occasioned from the Body, must needs be less natural to a Spirit? ...I would be glad also to
learn from these Men, who so confidently pronounce, that the humane Soul, or which is all
one, that a Man always thinks, how they come to know it; nay, how they come to know, that they
themselves think, when they themselves do not perceive it.” (Locke, An Essay concerning Human
Understanding II.1.17 and 18)
 Locke argues that every drowsy nod shakes this argument; later Kant followed Decsartes’s
argument, saying that a sleeper must always dream.
Dream argument
 This is the old problem from Plato in
Theatetus: ”I am awake or am I
dreaming?”Is reality only an illusion?
 Descartes differs from Plato and
Aristotle in supposing that dreams are
actual perceptions and his followers
and enemies followed this idea.
 In other words, when we are awake
we perceive and when we are asleep,
we continue perceiving. Because of
this, it may be diffult to separate the
waking and sleeping state from each
other.
 In short, Descartes’s answer is that
the waking life is more consistent
than dreaming life.
Dream argument in the 1st Meditation
“As if I were not a man who sleeps at night, and who often has all the same
experiences in dreams as madmen do when awake, or sometimes even less likely
ones. How many times has it happened that I have been convinced, in nightly rest,
that I am in this place, dressed in gown, sitting by the fire – when in fact I am lying
undressed in bed! Yet at this moment I am certainly looking at this piece of paper
with vigilant eyes; this head that I move is not asleep; I stretch out and feel my
hand deliberately and knowingly. What happens to someone asleep would not be so
distinct. But do I not remember that I have also been deceived in other occasions
by similar thoughts while asleep! Thinking about this more carefully, I see so plainly
that there are no sure signs by means of which being awake can be distinguished
from being asleep, that this astonishes me, and this very embarrassment almost
reinforces the thought that I may be asleep.Let us suppose then that we are
dreaming, and that these particulars – that we open our eyes, that we are moving
our heads and stretching out our hands – are not true. Perhaps, indeed, we do not
even have such hands nor such a whole body at all.
(Descartes, Meditationes de prima philosophia I, AT VII, 19)
Some dimension of the Dream argument
The argument has been very popular. It became one of the central sceptical hypothesis – one can doubt
everything, considering it all as a dream. The argument has influenced the idea of virtual reality. The ability of
the mind to be tricked into believing a mentally generated world is the "real world" means at least one variety
of simulated reality is a common, even nightly event. Those who argue that the world is not simulated must
concede that the mind—at least the sleeping mind—is not itself an entirely reliable mechanism for attempting
to differentiate reality from illusion.
 The dream argument has similarities to some views in Eastern philosophies. This type of argument is well
known as "Zhuangzi dreamed he was a butterfly”. One night, Zhuangzi (369 BC) dreamed that he was a
carefree butterfly, flying happily. After he woke up, he wondered how he could determine whether he was
Zhuangzi who had just finished dreaming he was a butterfly, or a butterfly who had just started dreaming he
was Zhuangzi. This was a metaphor for what he referred to as a "great dream":
”He who dreams of drinking wine may weep when morning comes; he who dreams of weeping may in the
morning go off to hunt. While he is dreaming he does not know it is a dream, and in his dream he may even try to
interpret a dream. Only after he wakes does he know it was a dream. And someday there will be a great awakening
when we know that this is all a great dream.Yet the stupid believe they are awake, busily and brightly assuming
they understand things, calling this man ruler, that one herdsman - how dense! Confucius and you are both
dreaming! And when I say you are dreaming, I am dreaming, too. Words like these will be labeled the Supreme
Swindle.Yet, after ten thousand generations, a great sage may appear who will know their meaning, and it will still
be as though he appeared with astonishing speed.”
 Some schools of thought in Buddhism (e.g., Dzogchen), consider perceived reality literally unreal. As a
prominent contemporary teacher, Chögyal Namkhai Norbu, puts it: "In a real sense, all the visions that we see
in our lifetime are like a big dream [...]". In this context, the term 'visions' denotes not only visual
perceptions, but appearances perceived through all senses, including sounds, smells, tastes and tactile
sensations, and operations on received mental objects.

More dimensions
 Many philosophically-influenced films
or novels are related to the argument.
Think Alice in Wonderland, Matrix (see
http://matrix.cultzone.com.br/Philos
ophy%20Dream%20Skepticism.htm),
Inception, Blade Runner etc.
 Some litterature: Peter J. Markie:
”Dreams and Deceivers in Meditation
One”, The Philosophical Review, vol 90, 2
(1981), pp. 185-209.; Robert Hanna:
”Descartes and Dream Scepticism
Revisited”, Journal of the History of
Philosophy, vol. 30, 3 (1992), pp. 377398; Brad Chynoweth: ”Descartes’
Resolution of the Dreaming Doubt”,
Pacific Philosophical Quarterly 91 (2010),
pp. 153-179
Distinction between dreams and waking life in the 6th Meditation
”For I know that in matters regarding the well-being of the body, all
my senses report the truth much more frequently than not. Also, I
can almost always make use of more than one sense to investigate the
same thing; and in addition, I can use both my memory, which
connects present experiences with preceding ones, and my intellect,
which has by now examined all the causes of error. Accordingly, I
should not have any further fears about the falsity of what my senses
tell me every day; on the contrary, the exaggerated doubts of the last
few days should be dismissed as laughable. This applies especially to
the principal reason for doubt, namely my inability to distinguish
between being asleep and being awake. For now I notice that there is
a vast difference between the two, in that dreams are never linked by
memory with all other actions of life as waking experiences are.”
(CSM II, 61)
The solution and an example
 Thus whereas in the 1st Meditation Descartes admits that dreams are sometimes difficult
to distinguish from waking state, in the 6th Meditation he argues that in waking state we
can trust that our memory connects things to each other, as we can trust the benevolence
of God to such an extent that our perceptions are equivalent to reality. In dreams this is
not the case and the things and event in the dreams are not connected to each other,
making the dreams strange and bizarre with no apparent relation between cause and an
effect and having no apparent connection to my life. This is why our memories of dreams
are inconstant and fragmentary. Descartes gives an example:
“If, while I am awake, anyone were suddenly to appear to me and then disappear
immediately, as happens in sleep, so that I could not see where he had come from or where
he had gone to, it would not be reasonable for me to judge that he was a ghost, or a vision
created in my brain, rather than a real man. But when I distinctly see where things come
from and where and when they come to me, and when I can connect my perceptions of
them with the whole of the rest of my life without a break, then I am quite certain that
when I encounter these things I am not asleep but awake. And I ought not to have even the
slightest doubt of their reality if, after calling upon all the senses as well as my memory and
my intellect in order to check them, I receive no conflicting reports from any of these
sources.For from the fact that God is not a deceiver it follows that in cases like these I am
completely free from error.” (CSM II, 61-62).
Remembering dreams
 Because the dream images
are so scattered, bizarre
and there seem not to be
cause and effect, our
memories of dreams are
very fragmentary.
 We can remember just
some vivid images which
are often very different
from our everyday
experience. TÄSTÄ LISÄÄ
Objections by Bourdin and Hobbes
 According to Bourdin, even
seemingly self-evident
principles could be mere
dreams. Descartes seems to
think the kind of self-evident
principles he regards essential
to waking life are related to
innate thoughts, that is, they
are related to God.
 In his objections to
Meditations (3rd objections),
Hobbes gives interesting
arguments against Descartes’s
views.
Hobbes on dream argument
 Hobbes starts with the dream argument, doubting that memory and waking state are connected:
”Consider someone who dreams that he is in doubt as to whether he is dreaming or not. My question is
whether such a man could not dream that his dream fits in with his ideas of a long series of past events. If
this is possible, then what appears to the dreamer to be actions belonging to his past life could be judged
to be true occurences, just as if he were awake. Moreover, as [Descartes] himself asserts, the certainty
and truth of all knowledge depends solely on our knowledge of the true God. But in that case an atheist
cannot infer that he is awake on the basis of memory of his past life. The alternative is that someone can
know he is awake without knowledge of the true God.” (CSM II, 137)
 Thus one can, by using the coherence-method judge that one is not dreaming when in fact one is
dreaming.
 A more serious objection by Hobbes concerns the validity of Descartes’s sceptical method. First
Hobbes argues that if dream fits well with the history of the dreamer, that is, remembered events,
one cannot distinguish between dreaming and waking state. Many dreams are not extravagant.
 What if one does not believe in God? Then God as the great connector of events to other cannot be
brought to help and ends up to a situation where one cannot know if one is awake or not or one can
know that oneis awake independently of God which would question the whole foundations of
Descartes’s metaphysics.
Descartes’s answer
 Descartes answers to Hobbes that a
dreamer can indeed connect the
dream to his earlier experiences,
but this is an illusion. The dreamer
dreams about these connections and
when he wakes up, he finds that he
has made a mistake. In other words,
one find that the dream images are
so scattered that he infers having
seen a dream.
 What about the atheist? An atheist
can rely on his or her earlier
memories and infer that one is
awake – he is just no aware of the
fact that the continuity and the
consistency is actually God’s doing.
But God is really the great
connector.
Malcolm on Descartes’ argument
 According to Norman Malcolm, Descartes is in fact saying that if I can’t
connect things I see in dreams to the events of my life, I have to
conclude that I am dreaming. Against this one could say that it makes no
sense to suppose that a person who is fast asleep to make judgements or
connecting things. Ergo: Descartes’s solution is not valid.
 However, Descartes is not saying that the connecting things or
judgement takes place in sleep. Instead, in the 6th Meditation he says
that the deliberation takes place when we are awake and we recall the
dream. When we are awake and we recall the dream, we note that there
are gaps and incoherence and therefore one can conclude that it has been
a dream.
 According to Bernard Williams, Descartes says that we can have
judgements in dreams, but as a rule they are incorrect. But in waking
state we are capable of valid reasoning and explain the sleeping state. But
when we are asleep, we cannot do this. Therefore Malcolm’s objection is
mistaken.
Leibniz’s admission
 Leibniz argues in De modo distinguendi
phaenomena reali ab imaginariis that the
distinction cannot in fact be demonstrated:
“It must indeed be admitted that the criteria of
real phenomena thus far offered are not
demonstrative, even taken together, although they
have the greatest probability, or popularly
speaking, they provide moral certainty, but do not
establish metaphysical certainty so that the
contrary claim would imply a contradiction. Thus
it cannot be absolutely demonstrated by any
argument that bodies exist, and nothing prevents
certain well-ordered dreams from being the
objects of our mind, which we judge to be true
and which, as regards practical matters, are
equivalent to truth because of their accord with
each other.” (A VI, 4, p. 1502)
 Thus there cannot be a demonstration of the
distinction, but Leibniz does not see it as a
serious problem.
Thomas Hobbes on Dreams
 Thomas Hobbes (1588-1679)
was a British philosopher,
most famous for his political
theory (Leviathan, 1651).
 He was also perhaps the most
profilic theorist of dreams in
England.
 Besides writings the
objections to Descartes, he
developed his own views on
dreams in The Elements of Law
Natural and Politic (1640),
especially in the first part
(Human Nature).
Dreams as imagination
 Hobbes followed Aristotle in thinking that in sleep the dreams are products of imagination. In
Hobbes they are a special type of imagination:
“The imaginations of them that sleep, are those we call Dreams. And these also (as all other Imaginations)
have been before, either totally, or by parcells in the Sense. And because in sense, the Brain, the Nerves,
which are the necessary Organs of sense, are so benummed in sleep, as not easily to be moved by the
action of Externall Objects, there can happen in sleep, no Imagination; and therefore no Dreame, but
what proceeds from the agitation of the inward parts of mans body; which inward parts, for the
connexion they have with the Brayn, and other Organs, when they be distempered, do keep the same in
motion; whereby the Imaginations there formerly made, appeare as if a man were waking.” (Hobbes,
Leviathan I.2)
 Thus Hobbes does not give dreaming a metaphysical role – sleeping is the lack of sense perception.
Like Aristotle, he is arguing that the images in sleep are clear and vivid because the sense organs
which cause confusion are shut down in sleep: “…the organs of sense being now benummed, so
there is no new object, which can master and obscure them with a more vigorous impression, a
Dreame must needs be more clear, in this silence of sense, than are our waking thoughts.” (Hobbes,
Leviathan I.2)
 Whereas Descartes saw dreams as scattered, weak and illogical images, Hobbes considers the dream
images as clear and powerful. We do not wonder strange images in dreams without a relevant cause
because wonder requies comparision with past events whereas in dreams everything is as it were
present at the same time.
 Hobbes also says that in dreams we always think that we are awake.
Physical causes of dreams
 Although Hobbes sees dreams as products of special kind of imagination, there is a physical
cause behind it. Imaginations take place when the internal organs press the brains:
“The causes of dreams (if they be natural) are the actions or violence of the inward parts of a man
upon his brain, by which the passages of sense, by sleep benumbed, are restored to their motion.”
(Human Nature, III, 3).
 Again like Aristotle, Hobbes saw dreams often related to illnesses and distempers in the body.
Different distempers produce different kinds of dreams.
“The signs by which this appareth to be so, are the differences of dreams proceeding from the
different accidents of man’s body. Old men being commonly less healthful and less free from
inward pains, are thereby more subject to the dreams, especially such dreams as be painful: as
dreams of lust, or dreams of anger, according as the heart, or the other parts within, work more
or less upon the brain, by more or less heat.” (Human Nature, III, 3).
 According to Hobbes, the bizarreness of dreams is not related to memory as in Descartes.
According to Hobbes, there is no consistency in dreams and if there is, it is a co-incidence.
 The reason for the bizarreness is the fact when the internal organs press the brains, the parts
of the brain do not return to motion at the same time during sleep. Thus there are powerful
images, but are not usually consistent.
The somatic theory of Hobbes
 According to Hobbes, somatic impulses often affect the content of our dreams.
Not only the illnesses, but also external conditions may affect the dreams. In
Leviathan he says:
”...And seeing dreames are caused by the distemper of some of the inward parts of
the Body; divers distempers must needs cause different Dreams. And hence it is,
that lying cold breedeth Dreams of Feare, and raiseth the thought and Image of
some fearfull object (the motion from the brain to the inner parts, and from the
inner parts to the Brain being reciprocall:) And that as Anger causeth heat in some
parts of the Body, when we are awake; so when we sleep, the over heating of the
same parts causeth Anger, and raiseth up in the brain the Imagination of an Enemy.
... In summe, our Dreams are the reverse of our waking Imaginations; The motion
when we are awake, beginning at one end; and when we Dream, at another.”
(Hobbes, Leviathan I.2)
 This somatic theory was influential for a long time, but the modern psychology
has shown that it is incorrect. These conditions can affect our sleeping, but not
the content of dreams.
Decaying sense
 As in Aristotle, Hobbes argues that
imagination is an image or decaying
perception which gradually changes
more and more confused.
 Like in imagination, our memory
decays with time, like when we are
in a foreign city and our memories
of it turn more and more confused
when time passes.
 For this reason there is no criterion
that will tell us whether we are
dreaming or not. One can dream of
doubting is this a dream or not [>
lucid dreaming], but it is certain
that images are much more detailed
and clearer in dreams than in
waking life.
Apparitions
 According to Hobbes, men often describe their past dreams as apparitions if the dream
concerned ordinary things. Hobbes seems to think that we can remember dreams better than
waking life images – the dream-images are experiences that are powered-up by the ceasing of
other senses.
 In Leviathan Hobbes has a long discussion on apparations [lucid dreaming] and visions. He says
that sometimes, for example, when we are full of fearful thoughts, we do not observe that we
have slept. We sleep clothed, nod off in public. Often in these cases there are apparations or
visions.
 For example, Brutus tells about Philippi who in the night before a great battle saw a fearful
apparation which is often thought to be a vision (happening while awake), but Hobbes thinks it
was a short dream caused by the anxiety of the battle. Philippi thought he saw a vision.
 God can make unnatural apparitions, but this is so common that there is nothing to be feared
for in these.
 Hobbes uses the distinction between apparition and vision to critisize past primitive religions
who believed in fairies, ghosts etc. He thinks withches are invented to glorify the crosses, holy
water etc. of the holy men. Utilizing superstition, some use apparations to mislead common
men. In other words, he rejects the Stoic divination-tradition.
”If this superstitious fear of spirits were taken away, and with it, prognostiques from dreams, false
prophecies, and many other things depending thereon, by which, crafty ambitious persons abuse
the simple people, men would be much more fitted than they are for civill obedience.” (Leviathan,
II, 7)
Pascal on dreams
 In Penseés (1658-62) Blaise
Pascal (1623-1662) argues
that if we saw similar dreams
each night, we would get
used to them:
”If we were to dream every
night the same thing, it would
probably have as much effect
upon us as the objects which we
see daily…but because our
dreams are all different, what
we see in them affects us much
less than what we see when we
are awake, on account of its
continuity…”
Malebranche on remembering dreams
 Malebranche has a more positive attitude to remembering dreams than
Descartes and he is especially concerned by sinful visions:
”It is fairly common for certain people to have dreams at night vivid enough to be
exactly recalled when they awake, even though the subject of their dream is not in
itself very terrible. And so it is not difficult for people to persuade themselves that
they have been to the witches’ sabbath, for it is sufficient for this that their brain
preserve the traces caused there during their sleep” (Malebranche, The Search After
Truth, II, 3, 6)
 However, his basic view is similar to Descartes: ”The chief cause that prevents
us from taking our dreams for reality is that we cannot connect our dreams with
the things we have done while awake, for this is how we recognize that they are
only dreams. Now imaginary witches cannot recognize by this means that their
witches sabbath is a dream, for they go to the witches sabbath only during the
night, and what happens at the sabbath cannot be connected to other actions
during the daytime. Hence, it is morally impossible to disabuse them in this
way…” (Malebranche, The Search After Truth, II, 3, 6)
Spinoza on dreams
 Baruch Spinoza (1632-1677) had a
necessitarian metaphysical system
where the mind and the body are
attributes of God or nature.
 As in many other respects, he
followed Hobbes’s views on
dreams. However, he argues that
when we are dreaming, we are
more adventurous and do things
which we would not do when we
are awake (especially sleepwalkers).
Despite necessitarianism, the
decisions made in dreams seem to
be free to the dreamer although
they are actually not free.
Spinoza on dreams and body
 Spinoza seems to follow the somatic theory
of Hobbes. For example, as we remember,
he explained the cause of seeing in dreams
a black brazilian as a consequence of a
delirium or sickeness of a body.
 According to Spinoza, when we are asleep,
the body does not register or react to our
decisions (for example, decision to go to
the lecture).
 A problem follows: if memory is
connecting those ideas that are outside of
the body or affects of the body (Ethics II,
p18, scholium), it would seem that there
cannot be memories about dreams as
without the body we cannot remember
anything (E5p21).Yet in his letter Spinoza
argues seeing a dream.
 Perhaps the problem can be helped by
arguing that we can remember some vivid
images but not decisions (on the other
hand, Spinoza says that there is no thinking
in dreams, either).
Dreaming & Thinking
 Contra Descartes, Spinoza does not allow thinking while sleeping. But in the Ethics III,
p2, note he says:
”Does not experience…teach that if…the body is inactive, the mind is at the same time
incapable of thinking? For when the body is at rest in sleep, the mind at the same time
remains senseless with it, nor does it have the power of thinking, as it does when awake.”
 In E IIp49 he discusses dreaming in more detail. He says that we should conceive a child
imagining a winged horse and not perceiving anything else (that is, dreaming). This
would mean that the child regards the horse as present although he cannot be sure that it
exists.
 Spinoza says that we find this kind of situation daily in our dreams: ”We find this daily in
our dreams, and I do not believe there is anyone who thinks that while he is dreaming he
has a free power of suspending judgment concerning the things he dreams, and of
bringing it about that he does not dream the things he dreams he sees. Nevertheless, it
happens that even in dreams we suspend judgement, viz. when we dream that we
dream.”
 What is he saying here? Apparently dreams and imaginations in general just come to us,
we cannot help seeing them. A winged horse is a vivid image (although it does not exist)
and we cannot question it. The child lacks the knowledge that would tell him or her that
this image could not possibly exist. As an exception, he mentions lucid dreaming
(dreaming that we dream).
Leibniz’s fragment on dreams
 Leibniz (1646-1716) had a large
project in his early years called
Demonstrationes catholicae,
including a short fragment on
dreams (it is to appear in Finnish
with an introduction in Niin &
Näin 4/2013)
 In the fragment (1668?) he
seems largely to agree with
Descartes, but also presents his
own views on dreams.
 The fragment is published in
Leibniz, Philosophical Papers and
Letters (ed. Loemker), pp. 113115.
Leibniz on lucid dreaming
 Leibniz has a comment on lucid
dreaming: ”…now and then the
dreamer himself observes that he is
dreaming, yet the dream continues.
Here he must be thought of as if he
were awake for a brief interval of time,
and then, once more oppressed by
sleep, returned to his previous state.”
 Related to this is the phenomenon of
trying to wake oneself up: ”Some men
can wake themselves up, and it is a
familiar experience of mine that, when
some pleasing vision presents itself, I
notice that I am dreaming and try my
eyes and pull them open with my
fingers to admit the light.” // here
Leibniz is probably referring to the
Augustinian problem – the pleasing
vision is related to sense pleasure which
is related to sin.
Other sinful problems of sleep
 Related to the same Augustinian question is the phenomenon of
falling out of bed which, according to Leibniz, are popularly
ascribed to lapses into sin. ”Sometimes when this has happened to
me, I can scarcely persuade myself to fall asleep all night. For in
the first moment of falling asleep, I suddenly recollect myself, and
sensing this fact, leap up.”
 Leibniz also comments the so-called wet dreams: ”Nor ought we
to overlook the spontaneous ejection of semen without any
contact in sleep; in wakers it is expelled only when they are
strongly agitated, but in sleep [animal] spirits are moved internally
by a strong imagination alone and without any rubbing of
members. I have also heard this confirmed by a physician.”
Cartesian argument
 According to Leibniz, when we are awake all our actions and thoughts are
directed at least impilicitly to the ultimate goal, that is, perfection, but when we
are dreaming ”there is no relation to the whole of things”.
 Waking up is to remember oneself, that is, to connect the present state to our
other events in life. In this sense Leibniz differs from Descartes: not only
memory, but also self-consciousness is required to be awake.
 For a general criterion between sleeping and being awake Leibniz presents that
we can be certain of our waking state only when we remember how we have
arrived to our present state and see how the things that appear to us are
connected to each other. In dreams we cannot see these connections and the
causes of our present state and we are not surprised by the lack of them.
 To Bayle Leibniz wrote: “God could have given each substance its own
phenomena, independent of all others; but in so doing he would have made as
many unconnected worlds, so to speak, as there are substances – rather as we
say that when dreaming one is in a world of one’s own, and one enters the
common world on awakening.”
Comment on Hobbes
 Leibniz also comments the remark by Hobbes where he says that in dreams
everything seems to appear without our finding them not at all strange or
bizarre.
 Objection: ”But, you say, surely we often experience judgment or reflection in
dreams, or at least a knowledge of the past which involves judgment, for we
both deliberate and remember.”
 Leibniz: This is because making judgements requires memory and if we do
judgements in our sleep, it is founded on our previous experiences although we
are not always aware of it. ”For entire conversations occur to us which are
certainly not without judgements about them, but because judgements already
made recur with the experiences themselves.”
 Therefore in dreams our judgements are founded only to impressions received
therein ja all the memory-images are blocked out. Because of this we accept
everything as normal – we cannot compare the dream images to waking images.
Content of dreams
 Leibniz is especially interested in the
bizarre content of dreams.
”There is one very remarkable thing in
dreams, for which I believe no one can give
a reason. It is the formation of visions by a
spontaneous organization carried out in a
moment – a formation more elegant than
any which we can attain by much thought
when we are awake.”
 In dreams our imagination is more free
than in waking state:
”To the sleeper there often occurs visions
of great buildings which he has never seen,
while it would be difficult for me, while
awake, to form an idea of even the smallest
house different from those I have seen,
without a great amount of thought.”
Inspired by dreams
 Leibniz brings out the creative effect of dreams – which we often do not
remember:
”I wish I could remember what marvellous discourses, what books and letters,
what poems beautiful beyond all doubt, but never previously read, I have read in
dreams without my shaping them at all, just as if they had just been composed and
offered to my sight.”
 These seem to arise without effort whereas when one is awake, a lot of work is
needed to produce them. Even such monstroties as flying man are more
difficult to picture when one is awake: ”They are sought by the waker, they offer
themselves to the sleeper”.
 Leibniz speculates that there must be some architectural or harmonious
principle in the mind which, when freed from separating ideas by judgement,
turns to compounding them.
 Finally, Leibniz says: ”A reason must be given why we do not remember waking
expriences in dream but do remember the dream when awake.” On this, Locke
disagreed, as we will see next.
Leibniz’s letter to Sophie Charlotte 1702
 Leibniz gives a special case concerning
dreams.
 He argues that if in a dream one finds a
demonstrative truth (for example the
Pythagorean theorem where in a right
triangle the square of the hypotenuse
(the side opposite the right angle) is
equal to the sum of the squares of the
other two sides), it would be equally
certain than if we were awake.
 According to Leibniz, this shows that a
distinct truth is independent of the
sensible and material things outside of
us. Although the dream images are, as a
rule, fragmentary, some distinct truth
can hit us in dreams and because it is so
vivid, we can remember it once we
wake up.
John Locke on Dreams
 John Locke (1632-1704) was the founder of
British empiricism. He argued that our mind
is like an empty drawing-table (tabula rasa)
when we are born, so we learn everything
about the world through experience.
 For Locke, dreaming is illogical: images
following each other as in Hobbes or
Descartes. In An Essay Concerning Human
Understanding II, I, §16-17 he sees dreams
perceptions as incoherent series of images.
 However, contra Descartes, we do not think
when we are sleeping and therefore we
cannot be happy or in misery during sleep as
this would require consciousness.
“Thus, methinks, every drowsy nod shakes their
doctrine, who teach that the soul is always
thinking” (E II, I, §13).
Dreaming and thinking
 Locke discusses a case when we the soul thinks during the sleep, but we just do not
remember it. But he is very sceptical of this:
”For who can without any more ado, but being barely told so, imagine, that the greatest part
of men, do, during all their lives, for several hours every day, think of something, which if
they were asked, even in the middle of these thoughts, they could remember nothing of
it?”(E II, 1, §14)
 Locke argues that most men pass a great part of their sleep without dreaming.
 He presents a different criterion than Descartes dream-argument: in the waking-state we
use the materials of the body when we think and our thinking leaves memory traces in
the brain, but in the sleeping state we do not use the bodily organs and therefore there is
left no memory traces in the brain and consequently we cannot remember the thoughts
in the dreams > there is probably do thinking in the sleeping state
 Instead, we can remember some of the perceptions of the dreams. Joining party with
Descartes, he says:
”How extravagant and incoherent for the most part they are; how little conformable to the
perfection and order of a rational being, those who are acquinted with dreams, need not be
told.” (E II, 1, §16).
 As on example of this he mentions duration: we very seldom have any ideas of duration
in dreams.
Dreams as waking man’s ideas
 Because the soul does not think
during sleep, dreams are really
fragments of our waking life:
”The dreams of sleeping men, are, as I
take it, all made up of the waking
man’s ideas, though for the most part,
oddly put together.” (E II, 1, §17)
 The idea looks to be the following:
in the waking state we think and
employ the organs of the body in
this thinking. They leave memory
traces to our brain. When we are
sleep, these traces are mixed
together and produce the dreams
but as they are only traces, not the
original thoughts, the dreams can
be strange.
Dreaming as having ideas
 In the end, Locke’s theory of dreams is not too far from Hobbes:
”Dreaming itself, is the having of ideas (whilst the outward senses are stopp’d, so that they
receive not outward objects with their usual quickness) in the mind, not suggested by any
external objects, or known occasion; nor under any choice or conduct of the understanding
at all. And whether that, which we call Extasy, be not dreaming with the Eyes open, I leave
to be examined.” (Locke, An Essay concerning Human Understanding II, 19, §1
 As there is no thinking in the sleeping state, the dreams are ”leftovers” from the waking
state which are more vivid in the sleeping state as bodily sensory organs are closed.
 Locke is not continuing Aristotle’s view of dreams as product of imagination as Hobbes
did, but rather dreams are memory traces or memory fragments mixed together.
 Locke also agrees with Hobbes that external things can affect our dreams: if we hear a
bell sound off, it can become part of the dream, likewise our movement during the sleep
(although there is no memory trace of these, so they are exceptions although not a result
of thinking while sleeping).
 This can happen also in another direction: when we dream having a fight, we can ”feel” a
punch although there is not one in the first place and according to Locke, we cannot feel
pleasure or pain in the dreams.
No criterion
 Although Locke in certain aspects agrees with Descartes, he does not admit that there is
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a general criterion to distinguish dreams from the waking state. He seems to think that
the ideas or memory traces we have in dreams can be of various strength and for this
reason, more or less vivid.
Because of this, he cannot agree with Hobbes that the waking experience is in principle
similar with the sleep experience. Supposing this would only make us suspicious towards
our own senses.
Locke’s view of dreams as a sort of puzzle of material from the waking state has a
striking similarity to some contemporary brain-research-orientated psychology. Robert
Stickgold who is part of Allan J. Hobson’s team has showed through his experiments that
during the REM-phase of the sleep the brains are activated and dreams consist of
memory fragments. In other words the memory in a way reorganizes itself during the
sleep.
This has interesting relations to learning: we can learn in dreams without being
conscious of it – thus Stickgold would hold against Locke (and agree with Descartes)
that we in fact ”think” in dreams. Sofar, there is no certain knowledge of this, but it is
probable that there will be in few years.
So someone should tell Hobson and Stickgold about Locke’s views!
George Berkeley on Dreams
 Bishop Goerge Berkeley’s (1685-1753) views on dreams
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


have to be looked in the framework of the DescartesHobbes-discussion. Like Malebranche, he largely agreed
with Descartes.
In his Three Dialogues Between Hylas and Philonous (1713)
Berkeley argued that images produced by imagination are
weak and confused and are wholly dependent on the will.
The ideas which are perceived by the senses are much
more vivid and clear, because they are brought to us by a
separate entity from us (God) and they are not
dependent on our will. In some sense, for Berkeley, life is
a dream as he supports a view, according to which only
that exist that we perceive (esse est percipi).
Compare, for example, the difference between dreaming
that one is looking at the sun and really looking at the
sun.
Therefore it is easy to distinguish the waking images from
dreams which are incoherent and strange. Berkeley does
not comment on remembering dreams.
Thus the real thing is always better than the dreamversion of the same thing.
Three Dialogues Between Hylas and Philonous
Hylas. But according to your notions, what
difference is there between real things, and
chimeras formed by the imagination, or the
visions of a dream, since they are all equally
in the mind?
Philonous. The ideas formed by the
imagination are faint and indistinct; they
have besides an entire dependence on the
will. But the ideas perceived by sense, that
is, real things, are more vivid and clear, and
being imprinted on the mind by a spirit
distinct from us, have not a like dependence
on our will. There is therefore no danger of
confounding these with the foregoing: and
there is as little of confounding them with
the visions of a dream, which are dim,
irregular, and confused.
Hume on dreams
 David Hume (1711-1776), a famous sceptic and
Scottish Enlightenment thinker had some
interesting remarks on dreams.
 In Dialogues Concerning Natural Religion (1779) he
says that popular religion is « sick man’s dream »
 In an essay «Of Suicide » he continues this theme:
a superstitious man is miserable in every scene, in
every incident of life. This concerns even sleep
itself, which banishes all other cares of unhappy
mortals, affords to him matter of new terror;
while he examines his dreams, and finds in those
visions of the night, prognostications of future
calamities. Thus for “normal” people dreams are
helpful in restoring their strength, but for
superstitious they are terrible, predicting future
horrors.
 In an Essay ”Of the immortality of the soul” he
says that sleep which is a very small effect on the
body, is attended with a temporary extinction,
that is, a great confusion in the soul. By this he
probably means epistemic confusion.
Early Modern natural explanations of dreams
All early modern thinkers seem to agree that dreams
really occur in sleep; thus they are not errors of memory,
as some recent philosophers suggest. The problem is what
brings about such events.
 The traditional received view claims that there are
exceptional dreams of supernatural origin, but that most
dreams are naturally caused: they either have simple
organic or physiological causes, or they result from
recent mental states. In this they follow Aristotle.
 There are some exceptions, however. Supported by
biblical evidence, there persisted a more or less occultist
faith in the possible supernatural information of dreams.
For example, the Rosicrucian Andreae wrote:

“Finally, I took my usual and surest way of escape, and
went to bed, after true and eager prayer that divine
providence would let my good angel to appear, and
instruct me in this troublesome case, as had many times
happened before, and this, praise God, also took place to
my best and to the true and hearty warning and
improvement of my neighbours.” (Andreae, Chymische
Hochzeit Christiani Rosencreutz)
Bodily causes of dreams
 The Galenic tradition doctrine of four
humours was still influentical and in
general Early ModernThinkers were
interested in physiological causes (such
as diets and bodily humours) and
dreams.
 Books of dream interpretation were
popular in the sixteenth and
seventeenth century, and ancient works
of Galen, Artemidorus and Synesius
were consulted for that purpose.
 One good example of this tradition is
Thomas Nashe’s The Terrors of the Night
(1594): “A dreame is nothing els but a
bubbling scum or froath of the fancie,
which the day hath left undigested, or
an after-feast made of the fragments of
idle imaginations.”
Dreams and mysticism
 As we saw, in his tale of his dreams
Descartes includes some mystical
elements, not far from Rosicrucians.
 Very often, religious mystical writers
affected the Early Modern conception
of dreams (this continued in the era of
Romanticism) – dreams were seen as
ecstatic visions where truths are
disconcealed.
 Sleepwalking had a special role. It was
thought that the soul leaves the sleeping
body and travels about, often in the
form of an animal, fighting the evil
spirits. This views was held, for
example, by Henry More in his Antidote
Against Atheisme.