Part Two: the external world

Part Two: the external world
Epistemology Part Two: the external world This Photo by Unknown Author is licensed under CC BY-NC-SA

Introduction Views Questions Three Views What do we really know?
What is the direct object of awareness when we perceive? Three Views Direct Realism ("naive realism" or "commonsense realism"). The immediate object of perception is a physical thing that exists independently of our awareness of it. Representationalism The immediate object of perception is a sense datum or sense impression‑which cannot exist apart from our awareness of it. The physical world exists independently of and is the cause of our perceptions. Physical objects give rise to sense data that we perceive, so we only have mediate knowledge of the external world.

Introduction Views Common Sense
Through the five senses: sight, hearing, touch, taste, and smell‑we directly perceive the real world. Tells us that the physical world exists independently of our awareness of it. Tells us that the things we perceive are pretty much the way we perceive them. Common sense supports naive or direct realism.

Introduction Views Science Casts doubt on common sense.
Bertrand Russell Naive realism leads to physics, and physics, if true, shows that naive realism is false. Therefore, naive realism, if true, is false; therefore it is false.

Introduction Views Science Tells us that
The physical objects we perceive are not what they seem to be. We never see things in the present. Light takes time to travel. Colors are not in the objects but are the way objects appear as they reflect light. Science Tells us that the sounds we hear, the flavors we taste, the sensations of touch, and the odors we smell are not what they seem to be. They are mediated through our ways of perceiving so we seldom or never experience them as they really are in themselves. Representationalism is more consistent with science than direct realism. Representationalism holds that the real world causes our appearances or perceptions by

Introduction Locke John Locke’s Representationalism (1632‑1704)
He attacks the notion that we have innate knowledge of metaphysical truths and argues that all our knowledge derives ultimately from sense experience. Locke held a causal theory of perception Processes in the external world impinge on the perceiver's sense organs. These in turn send messages to the brain, where they are transformed into mental events.

Introduction Locke Objects and Events in the Real World
(Energy coming to sense organs) Sense Organs (Signals to brain) Brain Event (Transformation from physical to mental event) Perceptual Experience Perceptual experience: percept or sense datum or sense impression. Introduction Locke

Introduction Locke Primary Qualities Secondary Qualities
Are inseparable from their objects and so truly represent them. Solidity (or bulk), extension, figure, movement (and rest), and number. These are the true building blocks of knowledge because they accurately represent features in the world. Secondary Qualities Not in the things themselves but are caused by the primary qualities. Include colors, sounds, smells, tastes, touch, and sensations. Types of powers or potentialities or dispositions that reside in a physical object.

Introduction Locke Primary and Secondary Qualities Substance
Secondary qualities are powers that produce sensations (perceptions) in the perceiver. The primary qualities cause the secondary qualities that we perceive and Secondary qualities are the ways things have of appearing to us. Example Substance Underneath all the qualities is substance, the foundation of matter itself. Locke assumes that there must be an ultimate source of reality that underlies the ideas presented in experience. This is "something I know not what."

Introduction Berkeley
Representationalism to Phenomenalism. There are problems with representationalism. If direct realism, via physics, leads to representationalism, representationalism, on philosophical reflection, seems to lead to phenomenalism. George Berkeley (1685‑1753) Accepts "immaterialism." Berkeley criticism of Locke's representationalism. The primary‑secondary qualities distinction was unsound. First: The primary qualities are no more "in" the objects of perception than are the secondary ones. Second: There were logical problems in the theory that our perceptions resembled physical objects ("an idea can be like nothing but an idea"). Third, he undermined the whole notion of substance that Locke needed to maintain his theory. What is the difference, between a "something I know not what" and nothing at all? Ultimately, Locke's representationalism leads back to skepticism.

Introduction Berkeley
Berkeley’s View Ideas exist in the mind alone. All perceived qualities are mental or subjective: their reality consists in being perceived ("To be is to be perceived"). There is no material world. Physical objects are simply mental events. All physical objects are mental phenomena that would cease to exist if they were not perceived. God is always perceiving them. Contemporary Phenomenalism It doesn't posit God as necessary to hold the physical world in existence. It views the physical world as a construct of ideas. Mill: objects are "permanent possibilities of sensation," meaning that if one were to get into the appropriate condition, one would experience the sense data.

Introduction W. T. State & C.H. Whitely
A. W. T. Stace (1886‑1967) Argues that the realist's view of the world as containing material objects behind the perceived world is an unjustified faith. The world of scientific discourse is not to be taken literally, but instrumentally, as providing useful fictions that help us to predict experiences. C. H. Whiteley (1911‑ ), provides a thorough critical assessment of the phenomenalist position, analyzing its strengths and weaknesses.

Introduction Two Puzzles for Sense Data Theories
Paradox of the nontransitivity of perception. Take three pieces of red colored paper. Suppose we cannot distinguish between samples A and B. Samples B and C are indistinguishable. But say we can distinguish between A and C! On the sense data account, this is puzzling, since we should be able to distinguish our sense data from one another.

Introduction Two Puzzles for Sense Data Theories
Puzzle of indeterminateness. Suppose we see a speckled hen. How many speckles does our sense datum hold? If we say that the number is indeterminate, we seem to have a paradox between the indeterminate sense datum and the determinate objects that are supposed to be represented.

Introduction Bertrand Russell
A defense of representational realism. Develops Locke's causal theory of perception in the light of contemporary science. Knowledge of physical objects is inferred from percepts in our brain. Russell concedes that phenomenalism is not impossible, but views it as implausible for reasons similar to Whiteley's.

Introduction John Searle
Presents a contemporary defense of direct realism. He holds to the similarity between beliefs and perceptions. Both are intentional in structure. Perception gives us direct access to physical objects. Searle's essay is important because it relates perception to other intentional states such as beliefs, desires, and memory. Searle addresses the main criticism against direct realism, the problem of illusion.

Introduction Charles Landesman
A defense of representationalism. He argues that nothing in the world exemplifies color. It is the impact of radiant energy on the nervous system that produces the appearance of color. Such illusions as color appearances have a biological function, helping us make closer discriminations in the world, Colors are features neither of the external world nor of the mind.

Rene Descartes (1596-1650) background
Life & Works Life Works Agenda Motivation Travel Inward Focus Goals

Rene Descartes method Methodology Mathematics Intuition Deduction
The Meditations on First Philosophy This Photo by Unknown Author is licensed under CC BY-NC-SA

Rene Descartes First Meditation
First Part Start & Goal Method Doubting the Senses Senses Dream Problem Painter Analogy Math: Skeptical Pause God & The Demon God The Demon

Rene Descartes Second Meditation
Skepticism & Certainty Method Skepticism The Foundation of Certainty: I am, I exist The Self Goal Rejected: The Body as Self A Thing That Thinks Rejected Human Body Air, Wind, Fire, Vapor, or Breath

Rene Descartes Second Meditation
Knowledge of His Existence is not via the Imagination Certainty The Wax Example The Wax How the Wax is Known Language & Errors Perception & Inference The Wax Proves He Exists Conclusion

Rene Descartes third meditation
Truth & God Standard of Truth: Clear & Distinct External Things God & Deception Does God Exist? Is God a Deceiver? Ideas Division of Thoughts Ideas& Truth Source of Ideas Ideas of External Objects

Rene Descartes Third Meditation
External Objects: Instructed by Nature External Objects: Ideas do not Depend on His Will External Objects: Resemblance Ideas, Reality & Causes Ideas & Reality Objective Reality Principle: The cause must contain at least as much reality as the effect. Formal Reality Eminent Containment Causes of Ideas Regress Argument for Archetypes

Rene Descartes Third Meditation
Method: Trying to find an idea he cannot be the cause of. He could be the cause of his ideas of secondary qualities. He could be the cause of his ideas of primary qualities. God Substance & Infinity Argument Infinity, God and Comprehension Descartes considers he might be the cause. Why Descartes cannot be the cause.

Rene Descartes third meditation
More on God Goal He is lacking, so he cannot be the author of his own being. Infinite Parts Argument Regress Argument Several Causes Parents Idea of God God is not a deceiver/

Rene Descartes Fourth meditation
God & Reason God is not a deceiver. Reason The Cartesian Circle The Possibility of Error Points of Certainty

Rene Descartes Fifth meditation
Third Proof of God The Proof Unique to God

Rene Descartes Sixth meditation
The External World The Problem Descartes as the cause. God as the cause. External objects cause the ideas. Illusions Nature of Objects

Rene Descartes Problems & Impact
Natural Light Principle & Doubt Infinity Contamination Problem Interactionism: Arnold Geulincx ( ) Parallelism Interactionism: Nicolas Malebranche ( ) Occasionalism Blaise Pascal

Rene Descartes Problems & Impact
Certainty Universal Science Reconciling Science & Religion Artificial Intelligence

Foundationalism & Coherentism: Motivations
Replying to the Skeptic Response to Skepticism Response Account of justification Justification Regress Problem The Regress A belief must be justified A belief is typically justified by another belief Regress: Belief A is justified by B, which is justified by C, ect. The regress must be stopped

Option 1: Unjustified Foundation A is inferred directly from B which is unjustified. Wittgenstein Problem Option 2: Biting the Bullet-Infinite Regress Chain A is justified by B, which is justified by C ad infinitum. Option 3: Coherentism A is justified by B, which is justified by C, which is justified by A, going in a circle.

Option 4: Foundationalism A is justified by B which is based on a foundational belief. Inferential chain Every justified belief is either A properly basic belief Ends in a chain of beliefs the last of which is self justified.

Foundationalism Background General Background Example: Plato
Forms Innate ideas Example: Aristotle & Aquinas Basic Truths Aquinas: Truth As known in itself Understood via an inquiry of reason. This Photo by Unknown Author is licensed under CC BY-SA

Foundationalism Descartes’ Goals in the Meditations
Tear down Create a new, infallible foundation Create a solid and certain superstructure Descartes’ Refutation of Skepticism Deduces the existence of God Deduces that God is benevolent and not a deceiver. Perceptual mechanisms Normally what we see is real Abnormal circumstances Empirical judgments Induction only a source of belief Indubitable basic principles & deduction

Foundationalism Criticism of Classic Foundationalism
Very little knowledge Only infallible or incorrigible beliefs in the foundation. Not enough self-evident truths. Empirical beliefs cannot be knowledge Tends towards skepticism.

Foundationalism Moderate Foundationalism General Idea Features
Foundational model Addresses criticism of classical foundationalism Rejects infallibility Accepts fallibilism Features Asymmetrical Doubts about psychological beliefs allowed Almost any belief can be basic Foundational relationship is on of justification Induction Coherence

Foundationalism Problem
Having a justification vs. being able to show it. Problem Not strong enough Incapable of replying to the skeptic. Addresses criticism of classical foundationalism Seems to compromise to coherentism

Coherentism Coherentist Theories of Justification Background
Truth resides in the absolute system of knowledge. Classic Coherentism Truth is not correspondence of propositions with facts. Truth is defined as integrated and absolute wholes Every truth belief is entailed by every other proposition 20th-21st century Coherentists Quine, Sellars, Harman, Lehrer, Bonjour Rejected the coherence theory of truth. Accepted a coherentist theory of justification. A belief is justified by the entire system of beliefs. This Photo by Unknown Author is licensed under CC BY-SA

Coherentism The Isolation Objection All justification is inferential.
Coherence seems inadequate Does not provide the necessary conditions to discern illusory but consistent sets of beliefs. We want to connect theories to empirical data. Consistency is necessary but not sufficient.

John Locke Background Background Early years & education Public life
Revolution Works The End Locke’s Project Age of enlightenment Motivation & task Methodology Ideas Historically plain method This Photo by Unknown Author is licensed under CC BY-SA

John Locke Empirical Epistemology
Critique of Innate Ideas Goals Innate Ideas Universal Agreement Universal Knowledge Moral Principles

Theory of Simple Ideas Origin of Knowledge Newtonian Influence Simple Ideas Type of simple ideas: Ideas of Sensation Type of simple ideas: Ideas of Reflection Only two sources of ideas.

Theory of Complex Ideas Origin of Complex Ideas Classification of Complex Ideas Compounding Abstracting & Abstract Ideas Primary & Secondary Qualities Qualities Primary Qualities Secondary Qualities Powers Locke’s general reasoning for the distinction

Representative Realism & Judgment Representative Realism Judgment The Mohneaux Problem Degrees of Knowledge Knowledge Intuitive knowledge Demonstrative knowledge Sensitive Knowledge Certainty

Refutation of Skepticism The Skeptic Locke’s Humorous Reply First confirmation: production of ideas Second confirmation: unavoidable Third confirmation: pain & measurement Fourth confirmation: Sense support each other Adequate Practical approach

David Hume Background General Background Goals Life & Writings
Other publications & career Goals Motivation Goal This Photo by Unknown Author is licensed under CC BY-SA

David Hume Epistemology &Metaphysics: Theory of Ideas
Perceptions Impressions Creative power of the mind Association of Ideas Atomism Association

David Hume Epistemology &Metaphysics: Theory of Ideas
Relations of Ideas & Matters of Fact Division Relation of Ideas Matters of Facts The Gap

David Hume Skepticism Regarding the Senses
The Sense & Objects Questions Why do we attribute continued existence? Why do we suppose distinct existence? Senses & continued existence Senses & distinct existence Self & Objects Intent External existence We do not perceive our body Sounds, tastes, etc. Sight does not inform us of distance immediately

Philosophers & the Vulgar Three types of impressions Primary Secondary Pains & pleasures Reason Contrary conclusions Imagination Vividness & involuntariness

Constancy, Coherence, Cause & Effect Motivation Constancy Coherence & Constancy Difference between external & internal impressions The room, porter & letter example. Reasoning from coherence vs. reasoning from cause & effect Regularity in perceptions Imagination in perceptions

Constancy Continued existence Distinct existence Neither an Independent nor Continued Existence Experience Experiments Additional confirmation of dependence

Philosophic & Vulgar Systems The philosophic system Hume’s criticism First part of the proposition Philosophical as palliative remedy Second part of the proposition Philosophical has the difficulties of the vulgar Explanation of the connection

Double Existence Reason & natural impulses Psychology of double existence Opinions Another advantage Results First particular Second particular Hume’s results Illusions & problems Skeptical doubt

Part Two: the external world

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