1. Overview
   1. knowledge comes only or primarily from sensory experience
   2. emphasizes the role of experience and evidence, especially sensory experience, in the formation of ideas, over the notion of innate ideas or traditions
   3. traditions (or customs) arise due to relations of previous sense experiences
   4. emphasizes evidence, especially as discovered in experiments
   5. fundamental part of the scientific method
      1. hypotheses and theories must be tested against observations
   6. rather than resting solely on a priori reasoning, intuition, or revelation
   7. "knowledge is based on experience"
   8. "knowledge is tentative and probabilistic, subject to continued revision and falsification."
   9. sensory experience creates knowledge
   10. experiments and validated measurement tools, guides empirical research
2. Background
   1. no knowledge to be properly inferred or deduced unless it is derived from one's sense-based experience
   2. contrasted with rationalism
      1. knowledge may be derived from reason independently of the senses
3. Early empiricism
   1. tabula rasa
      1. "clean slate" or "blank tablet"
      2. mind as an originally blank or empty recorder on which experience leaves marks
      3. denies that humans have innate ideas
   2. Aristotle
      1. theory of potentiality and actuality
      2. experience of sense perceptions still requires the help of the active nous
      3. contrasted with Platonic notions of the human mind
         1. entity that pre- existed somewhere in the heavens, before being sent down to join a body on Earth
         2. Phaedo
         3. Apology
   3. Stoic school
      1. the mind starts blank, but acquires knowledge as the outside world is impressed upon it
   4. Islamic philosophers
      1. Al Farabi
      2. Avicenna
         1. tabula rasa is a pure potentiality that is actualized through education
         2. knowledge is attained through "empirical familiarity with objects in this world from which one abstracts universal concepts"
         3. developed through a "syllogistic method of reasoning in which observations lead to propositional statements which when compounded lead to further abstract concepts
         4. intellect itself develops from a material intellect, which is a potentiality "that can acquire knowledge to the active intellect
      3. Ibn Tufail
      4. Abu Bakr Ibn Tufail
         1. tabula rasa as a thought experiment in his Arabic philosophical novel, Hayy ibn Yaqdhan
         2. influence on John Locke's formulation of tabula rasa in An Essay Concerning Human Understanding
   5. Thomas Aquinas
      1. senses are essential to mind into scholasticism
4. Renaissance Italy
   1. Niccolò Machiavelli
      1. people should study the "effectual truth"
   2. Francesco Guicciardini
   3. Leonardo da Vinci
      1. abandon the authority and base your reasoning on your own findings
   4. Vincenzo Galilei
      1. successfully solving musical problems
         1. tuning such as the relationship of pitch to string tension and mass in stringed instruments, and to volume of air in wind instruments
         2. through his tuning research, found the underlying truth at the heart of the misunderstood myth of 'Pythagoras' hammers' (the square of the numbers concerned yielded those musical intervals, not the actual numbers, as believed)
         3. to composition, by his various suggestions to composers in his Dialogo della musica antica e moderna
      2. essential pedagogical influence upon the young Galileo, his eldest son
5. British empiricism
   1. term used to describe differences perceived between two of its founders of modern philosophy and modern science
      1. Francis Bacon
         1. empiricist
      2. René Descartes
         1. rationalist
   2. next generation
      1. Thomas Hobbes
         1. empiricist
      2. Baruch Spinoza
         1. rationalist
   3. empiricists in 18th century Enlightenment
      1. John Locke
         1. normally known as the founder of empiricism
         2. response to the early-to-mid-17th century "continental rationalism"
         3. An Essay Concerning Human Understanding
         4. the only knowledge humans can have is a posteriori, i.e., based upon experience
         5. There are two sources of our ideas: sensation and reflection
         6. a distinction is made between simple and complex ideas
            1. former are unanalysable, and are broken down into primary and secondary qualities
            2. Primary qualities are essential for the object in question to be what it is
            3. Secondary qualities are the sensory information we can perceive from its primary qualities
         7. complex ideas combine simple ones simple ones, and divide into substances, modes, and relations
         8. our knowledge of things is a perception of ideas that are in accordance or discordance with each other
      2. George Berkeley
         1. Locke's view immediately opened a door that would lead to eventual atheism
         2. Treatise Concerning the Principles of Human Knowledge
         3. things only exist either as a result of their being perceived, or by virtue of the fact that they are an entity doing the perceiving
         4. any order humans may see in nature is the language or handwriting of God
         5. subjective idealism
      3. David Hume
         1. moved empiricism to a new level of skepticism
         2. divided all of human knowledge into two categories
            1. relations of ideas
            2. ex. Mathematical and logical propositions
            3. matters of fact
            4. contingent observation of the world
         3. ideas", in turn, are derived from their "impressions
            1. Ideas are therefore the faint copies of sensations
         4. all knowledge, even the most basic beliefs about the natural world, cannot be conclusively established by reason
         5. beliefs are more a result of accumulated habits, developed in response to accumulated sense experiences
         6. problem of induction
            1. it requires inductive reasoning to arrive at the premises for the principle of inductive reasoning
            2. the justification for inductive reasoning is a circular argument
            3. there is no certainty that the future will resemble the past
            4. we cannot know with certainty by inductive reasoning that the sun will continue to rise in the East
         7. belief in an external world and belief in the existence of the self were not rationally justifiable
         8. these beliefs were to be accepted nonetheless because of their profound basis in instinct and custom
         9. lasting legacy, however, was the doubt that his skeptical arguments cast on the legitimacy of inductive reasoning
6. Phenomenalism
   1. an extreme empiricist theory
   2. a physical object is a kind of construction out of our experiences
   3. the view that physical objects, properties, events (whatever is physical) are reducible to mental objects, properties, events. Ultimately, only mental objects, properties, events, exist
   4. to have a visual experience of a real physical thing is to have an experience of a certain kind of group of experiences
   5. John Stuart Mill
      1. matter is the "permanent possibility of sensation"
      2. induction is necessary for all meaningful knowledge including mathematics
      3. mathematical truths were merely very highly confirmed generalizations from experience
      4. no real place for knowledge based on relations of ideas
      5. logical and mathematical necessity is psychological
      6. most extreme version of empiricism known, but it has not found many defenders
      7. knowledge of any kind is not from direct experience but an inductive inference from direct experience
      8. problems other philosophers have had with Mill's position
         1. encounters difficulty when it describes what direct experience is by differentiating only between actual and possible sensations
         2. misses some key discussion concerning conditions under which such "groups of permanent possibilities of sensation" might exist in the first place
            1. Berkeley put God in that gap
            2. Mill, essentially left the question unanswered
         3. lacking an acknowledgement of an aspect of "reality" that goes beyond mere "possibilities of sensation"
         4. leads to a version of subjective idealism
         5. how trees continue to grow while unobserved and untouched by human hands, etc., remain unanswered
         6. leaves open the unsettling possibility that the "gap-filling entities are purely possibilities and not actualities at all
         7. by calling mathematics merely another species of inductive inference, misapprehends mathematics
         8. fails to fully consider the structure and method of mathematical science,
   6. ended by the 1940s
      1. statements about physical things could not be translated into statements about actual and possible sense data
      2. there is no finite set of statements about actual and possible sense-data from which we can deduce even a single physical-object statement
      3. no finite set of statements that are couched in purely sensory terms and can express the satisfaction of the condition of the presence of a normal observer
7. Logical empiricism
   1. also logical positivism or neopositivism
   2. synthesize the essential ideas of British empiricism
      1. with certain insights from mathematical logic
         1. Gottlob Frege
         2. Ludwig Wittgenstein
   3. key figures
      1. Otto Neurath
      2. Moritz Schlick
      3. A.J. Ayer
      4. Rudolf Carnap
      5. Hans Reichenbach
      6. Vienna Circle
   4. saw in the logical symbolism a powerful instrument that could rationally reconstruct all scientific discourse into an ideal, logically perfect, language that would be free of the ambiguities and deformations of natural language.
      1. Gottlob Frege
      2. Bertrand Russell
   5. combining:
      1. Frege's thesis that all mathematical truths are logical
      2. Wittgenstein's idea that all logical truths are mere linguistic tautologies
   6. arrived at a twofold classification of all propositions:
      1. analytic (a priori)
      2. synthetic (a posteriori)
   7. verification principle
      1. demarcation between sentences that have sense and those that do not
      2. most metaphysical, ethical, aesthetic and other traditional philosophical problems came to be considered pseudoproblems.
   8. abandoned this sort of phenomenalism in favor of a rational reconstruction of knowledge into the language of an objective spatio-temporal physics
   9. instead of translating sentences about physical objects into sense-data, such sentences were to be translated into so-called protocol sentences
      1. "X at location Y and at time T observes such and such."
   10. central theses
       1. verificationism, the analytic-synthetic distinction, reductionism, etc.
   11. came under sharp attack
       1. Nelson Goodman
       2. W.V. Quine
       3. Hilary Putnam
       4. Karl Popper
       5. Richard Rorty
   12. contemporary analytic philosopher
       1. Michael Dummett
       2. anti-realists
8. Pragmatism
   1. Charles Sanders Peirce
      1. "pragmaticism"
         1. integrates the basic insights of empirical (experience- based) and rational (concept-based) thinking
      2. highly influential in laying the groundwork for today's empirical scientific method
      3. concurred with the main ideas of rationalism
         1. the idea that rational concepts can be meaningful and the idea that rational concepts necessarily go beyond the data given by empirical observation
         2. emphasized the concept-driven side of the then ongoing debate between strict empiricism and strict rationalism
            1. to counterbalance the excesses to which some of his cohorts had taken pragmatism under the "data-driven" strict-empiricist view
      4. to place inductive reasoning and deductive reasoning in a complementary rather than competitive mode
      5. abductive reasoning
         1. the objects of knowledge are real things
         2. the characters (properties) of real things do not depend on our perceptions of them
         3. everyone who has sufficient experience of real things will agree on the truth about them
         4. primary conceptual foundation for the empirically based scientific method today
      6. The rationality of the scientific method does not depend on the certainty of its conclusions, but on its self-corrective character: by continued application of the method science can detect and correct its own mistakes, and thus eventually lead to the discovery of truth"
      7. three cotary propositions of pragmatism
         1. the peripatetic-thomist observation
            1. link between sensory perception and intellectual conception is a two-way street
            2. whatever we find in the intellect is also incipiently in the senses
            3. perception itself can be seen as a species of abductive inference
            4. it is beyond control and hence beyond critique
            5. incorrigible
            6. it is only the immediate percept in its unique individuality or "thisness"
            7. haecceity
            8. Scientific concepts
            9. are general in nature, and transient sensations do in another sense find correction within them
            10. notion of perception as abduction has received periodic revivals in artificial intelligence and cognitive science research
            11. Irvin Rock on indirect perception
   2. William James
      1. "radical empiricism"
         1. offshoot of his form of pragmatism
      2. the empirically observed "directly apprehended universe needs ... no extraneous trans-empirical connective support"
      3. to rule out the perception that there can be any value added by seeking supernatural explanations for natural phenomena
   3. John Dewey
      1. modified James' pragmatism
         1. instrumentalism
      2. experience as unified totality of things through which everything else is interrelated
      3. reality is determined by past experience
      4. humans adapt their past experiences of things to perform experiments upon and test the pragmatic values of such experience
      5. value of such experience is measured experientially and scientifically
      6. results of such tests generate ideas that serve as instruments for future experimentation