Plato revisited The Problem of Knowledge and the Knowable
The Forms and Reason, truth is possessed within and is ‘remembered’
Senses will not lead to truth Nativistic and fatalistic
Compare to modern theories of cognition and genetic underpinnings of intelligence etc.
The Problem of Conduct Reason controls the appetites, passion in aid of reason
strengthens resolve (harmonic existence) The unjust are not happier any more than the sick are relative
to the healthy The Problem of Governance
The polis is the extension of man and has the same ‘components’ of the soul: rational, appetitive, sensing
Aristotle ~384 BC – 322 BCE Student of Plato, eventually set up the Lyceum as a
rival to Plato’s Academy Categorized and catalogued a large number of
observations made of physical and biological phenomena
Treated many topics relevant to psychology Plato – truths in the forms that exist independent of
nature, known only by using reason (rationalism) Aristotle – essences could be known only by studying
nature through individual observation of phenomena (empiricism)
Aristotle embraced both rationalism and empiricism. Mind must be employed to gain knowledge
(rationalism), object of rational thought was information from sensory experience.
Contrasting views of Plato and Aristotle set stage for epistemological arguments throughout history
Aristotle’s logic The founder of formal logic
Deduction, syllogisms An argument consisting of three parts, a major
premise, a minor premise, and a conclusion Interested in determining what
combinations of premises in which all, some, none lead to which valid conclusions using the same terms
Examined categorical claims as well as hypothetical, such as if p then q but p is impossible so q is
Aristotle’s Science Science as it would eventually progress to
could be said to have started with Aristotle Although not providing a quantitative
description as today’s scientists would, he was a keen observer (well, usually) that sought to understand the world around him based on what could be perceived physically
For him it was an investigation of the forms which nature takes
Aristotle’s Science Some observations of the natural world
Thinking occurred in the heart Guys have more teeth than gals
For some reason he didn’t actually check this Falling bodies fall at steady speeds Dolphins give birth to live young and were
classified as ‘beasts of the field’ rather than sea
Hierarchy of species – the beginnings of an evolutionary theory
Aristotle: Actuality vs. Potentiality Form is something that nature approximates to,
but is not separate from nature Kind of like a prototype Distinguishes Potential vs. Actual
Matter – potentiality Form - Actuality Matter is responsible for the deviations from the norm
The form sets in place restrictions on what can be, and the task of the scientist is to discover the form in the variations for which matter is responsible
Discovery of the form is to understand what applies to all things of a certain type
God is pure form without matter or potentiality
Aristotle and the problem of universals One can see in his science the method
of induction, observing the particulars to come to some generality
Anything will do as a premise, it just must be agreed upon Operational definition
The study of nature is the study of change, and for Aristotle that change had to begin somewhere The Prime, or Unmoved Mover
A final cause
Aristotle: Cause To understand object or phenomenon we must
know its causes Four answers to the question ‘For what reason?’ Material cause
Matter of which it is made Formal cause
Form or pattern of the object Efficient cause
Force that transforms the matter Final cause
Purpose – why it exists
Aristotle: Purpose Everything has a purpose –
Teleology Everything has a function built into it (entelechy)
Entelechy keeps an object moving and developing in its prescribed direction to full potential
What gave everything in nature its purpose (entelechy) was the unmoved mover - caused everything in nature but was not caused by anything itself.
It set nature in motion and little else – it was a logical necessity
Compare these views to later pragmatism/functionalism, Peirce’s chance as the root cause?
Aristotle’s Metaphysics Metaphysics: ‘after Physics’
Science of what is Beings can be divided into ten distinct categories
Substance, quality, quantity, place etc. Substance
The primary kind of thing All others depend on substance
E.g. color in some object that is What is substance? Essence, universal, genus, and subject?
the essence of x, or some universal predicated of x, or a genus that x belongs to, or a subject of which x is predicated.
Substance for Aristotle is equated to subject “The substance of each thing is that which is peculiar to it, which
does not belong to anything else”. The form
Aristotle’s Ethics Conduct Every action aims toward some good For man it is eudaimonia, the activity of
the soul in accordance with excellence Man fulfilling his potential leading to
happiness in living the good life Doctrine of the Mean
Virtue as the mean Every ethical virtue is a condition intermediate
between two other states, excess and deficiency
Aristotle on the Soul The soul Inseparable from the body (its form), necessary for life
No soul surviving after death? “It is not necessary to ask whether soul and body are one, just as it is not
necessary to ask whether the wax and its shape are one, nor generally whether the matter of each thing and that of which it is the matter are one. For even if one and being are spoken of in several ways, what is properly so spoken of is the actuality”
Hierarchy of the soul, each necessary for the next, more advanced species will possess the other parts of the soul, up to humans with a mind
Vegetative (nutritive) soul – provides growth, assimilation of food, and reproduction.
Possessed by plants. Sensitive soul – functions of vegetative soul plus the ability to sense
and respond to the environment, experience pleasure and pain, and use memory.
Possessed by animals. Rational soul – functions of vegetative and sensitive souls plus ability
of thinking and rational thought. Only humans have the capacity for a rational soul
Aristotle on the Soul Functions of the soul
Nutritive Appetitive Sensory Locomotive Thinking
Livings things differ with respect to which functions of the soul they possess, the latter alone is linked with man
Aristotle’s Psychology Aristotle is perhaps our first true
psychologist (or at least physiological psychologist)
Was not materialistic per se*, but did try to understand psychological problems with an eye to the underlying physiology
Concept of mind (nous) is distinct from soul (anima), though may be a type of soul along with others; does not die with the body
*Trying to ‘categorize’ Aristotle’s views is a bit problematic
Aristotle: Sensation and Perception Sensation and Perception – information
about the environment is provided by from the five senses
Perception explained by motion of objects that stimulate a particular sensory system Senses as motion detectors E.g. seeing results from movement of light,
touch from movement of flesh We can trust our senses to yield at least
a somewhat accurate representation of the real world environment
Aristotle: Imagery Imagination and dreaming Imagination lies between perception
and reason Depends on sensory experience but
uses thought also Dreaming
Images from past experience which are stimulated by events inside or outside the body
Aristotle: Perception and Thinking General cognition Mind (intellect or reason) as the part of the soul by which
it knows and understands Has the potential for thought, but must impacted from
without in order for this to be actualized Common sense, distinct from the typical 5 senses,
passive and active reason Sensory information is only first step in gaining
knowledge – necessary but not sufficient element in obtaining knowledge
Information from multiple sensory systems must be combined
Common sense coordinates, synthesizes information from all of the senses for more meaningful and effective experience
Perceptual organization
Aristotle: Thinking Passive reason
Uses synthesized experience to function in everyday life.
Active reason (epistemonikon) Uses synthesized experience to abstract
principles and essences Highest form of thinking
Active reason provides humans with their entelechy – purpose is to engage in active reason, source of greatest pleasure.
Aristotle: Learning and Memory Memory, recall, and laws of association Remembering
Spontaneous recollection of a previous experience Recall
An active mental search for a previous experience Practice of recall affected by laws of association
law of contiguity – associate things that occurred close in time and/or in same situations
law of similarity - similar things are associated law of contrast – opposite things are associated law of frequency – more often events occur together, the
stronger the association Laws of association are basis for most theories of
learning and association
Aristotle: Emotion and Motivation Motivation and happiness
Happiness is doing what is natural – fulfills one’s purpose Purpose for humans is to think rationally.
Humans, being biological organisms, are motivated by appetites Humans however can use rational powers to inhibit our appetites Conflicts arise between immediate satisfaction and biological
drives and more remote rational goals. Aristotle, like most Greeks, held self-control and moderation
as a high ideal – the best life was one lived in moderation and control.
Doctrine of the mean Emotions and attention
Emotions function to amplify any existing tendency (behavior) Emotions also influence person’s perception to be more selective
Greek Physiology Early medicine – temple medicine, healing rituals practiced by
priests (kept secret and guarded), accompanied by much ritual and ceremony by patients.
Alcmaeon ~6th century BCE? Naturalized medicine
Proposed a balance of physical qualities needed for health “Alcmaeon said that the equality (isonomia) of the powers (wet,
dry, cold, hot, bitter, sweet, etc.) maintains health but that monarchy among them produces disease.”
The physician’s job was to help the patient regain equilibrium, the idea of balance and harmony for health has continued to present time
Through research concluded that sensation, perception, memory, thinking, and understanding occurred in the brain.
“All the senses are connected in some way with the brain. As a result, they are incapacitated when it is disturbed or changes its place, for it then stops the channels, through which the senses operate.”
Although thought by many to be among the first to do so, actually probably did not practice dissection
Greek Physiology Hippocrates ~460 - 377 BCE
“Father of Medicine” Hippocrates proposed that all disorders (mental and physical)
are caused by natural factors such as inherited susceptibility, organic injury, and by imbalances in bodily fluids
Humans are made of four humors which need to stay in balance for health
Phlegm Blood Yellow bile Black bile
The body has the ability to heal itself – physician’s job was to facilitate through natural healing – treat the whole patient, not just the disease
What happened to that idea?
Greek Physiology Galen (much later, 129-
200 CE) associated the four humors of Hippocrates with four temperaments and produced a rudimentary theory of personality
If one of the humors dominates, the person displays characteristics associated with that humor
Humor Temperament Characteristic
Phlegm Phlegmatic Sluggish
Blood Sanguine Cheerful
Yellow bile Choleric Short-tempered
Black bile Melancholic Sad
Importance of Greek thought In Popper’s view, science began when humans
began to question the prevailing stories about themselves and the world
The Greek cosmologists broke loose from the accepted traditions and speculated about the nature of man and the universe, also engaged in critical discussion
After Aristotle’s death, philosophers either relied on teachings of past authorities, particularly Aristotle, or turned attention from descriptions of the universe to models of human conduct
The critical, questioning tradition of the Greeks was subdued until revived in the Renaissance
Cynicism Cynicism
back-to-nature philosophy Antisthenes ~445-365 BCE
Pupil of Socrates Diogenes ~412-323
Largely thought themselves Socratic while preaching an austere view of the conduct of life
Contrast with the Cyrenaics who advocated the pursuit of pleasure
Diogenes by John William Waterhouse, 1882
Cynicism Life free of wants, pleasures, and conventions of society, true
happiness depends on self-sufficiency, quest for simple, independent natural life.
Seek virtue What is practical, efficient?
Cynics argued that animals provide the best model for human behavior
The dog as symbol of the school Needs are natural, as are the satisfaction of
“Nothing natural can be bad” ~ Diogenes (who would fart loudly in crowded places, urinate, masturbate
etc. in public) No religion
Primary message was that nature should guide human behavior, social conventions, including religion, were human inventions and cause shame, guilt, hypocrisy, greed, envy, and hate.
Epicureanism Epicureanism
philosophy of materialism, free will, no supernatural influences in the world, and no after-life
Epicurus ~341-270 BCE Lucretius ~96-55
Epicureanism Epicurus took physics almost entirely
from Democritus’ atomism Atoms fall through the void, as they do,
they swerve, collide and combine to form the matter we see
Lucretius extended the idea to the topic of free will, suggesting it is the swerve among the atoms of which the soul is made up Free will as the product of randomness
(indeterminism)
Epicureanism The ‘quadruple remedy’
Do not fear the gods The gods have no concern for us Are separate from humans, in another realm of the void
Do not fear death Death is nothing to us Simply the dissolution of atoms
Do not fear pain Pain does not last long Pleasure and pain as arising from the interaction of
atoms with those of the body and soul Pleasure is natural, pain short relative to pleasure,
pleasure as the removal of pain Pleasure is easy to obtain
Epicureanism Pleasure of three kinds
Natural and necessary E.g. the simple removal of pain
Natural but not necessary That which is not natural
Pursuit of the first is ideal In other words, not hedonistic Strive for tranquility that comes from balance between lack
of or an excess of anything, life of moderation. The good life is thus realizable and should be our goal
The good life was free, simple, rational, and moderate.
Epicureanism Epistemology All perceptions true All we have as a source of knowledge is
sense perception The action of atoms on the sense organs
and soul Thought not independent of sensory
knowledge Thus a completely empiricist approach
Stoicism All things outside of objects of thought are
corporeal (including soul) Materialistic view
Believed in a soul of the world (pneuma) World seen as organic
World ruled by a divine plan (the form of its matter) and everything in nature is there for a reason
Everything happens for a reason, no accidents, all must simply be accepted as part of the plan
Principal vs Proximate causes Soft determinism- approximate cause reacting to sense
perception but there has to be someone there first, the person and their nature which is the primary cause
Stoicism The good life involves accepting one’s fate
with indifference Only personal freedom was in choosing
whether to act in accordance with nature’s plan
Perfect duty Adhering to the highest good: being totally in accord
with reason Free from passions which distort truth
Imperfect duty Getting by with the obligations of everyday life Live without the insight of the sage
Stoicism Epistemology Emphasis on knowledge through sense-
perception An analogy:
Stimulus as the open hand Bending of fingers assent to it (attention) Clenched fist as apprehension The fist enclosed by the other hand true knowledge
Thus truth is to be arrived at by reason about experience
Skepticism Skepticism
suspension of belief
Pyrrho ~360-270 BCE The ‘New’ Academy Sextus Empiricus ~2nd century CE
Chronicler of skeptical thought Lucian 120-200
The Sale of Philosophers
Skepticism Pyrrho claimed that nothing could be known with certainty and
that this understanding was the key to happiness, free from care
Even lived as such Skepticism proposed that arguments for and against any
philosophical doctrine are equally compelling Noted that whatever one believed, it could turn out to be
false, thus, one could avoid frustration of being wrong by not believing in anything
Two guides for living, appearances and convention Sensation/Feeling Adherence to custom without formal beliefs
Arcesilaus later introduced the skeptical doctrine to the Academy and began the attacks on the dogmatists, or those philosophers who claimed some things could be known as true
Skepticism Carneades(~214–129 B.C.E.) followed,
introducing the notion of probability as a substitution for truth
No final criterion of truth Three grades of probability
The merely probable The probable and confirmed The probable, confirmed and tested
Such a view of the ideas of Carneades places him as an important figure in the philosophy of science
Theory Falsification/confirmation Probability
Skepticism Later (formal) Skepticism Aenesidemus
Skepticism as inquiry All we have are appearances, which conflict
10 modes or types of differences that suggest perceptual relativity
Differences in animals, humans, senses, perception, frequencies etc.
So much out there that truth in absolute sense is not possible
Suspend belief Suspension of belief leads to tranquility of the
mind