PHILOSOPHY 100 (Ted Stolze) Notes on James Rachels, Problems from Philosophy

Chapter Ten: Our Knowledge of the World around Us

Four Positions on the Mind’s Relationship to the External World Direct Realism (Aristotle, the Buddha) Cartesian Theological Realism Subjective Idealism (George Berkeley) The Commonsense View (Indirect Realism)

Direct Realism (1) “Seeing is a way of getting information about the world around us. But it is not a two-step process, in which we first get information about ‘sense-data’ and then move from that to information about the tree. Instead, it is a one-step process of seeing the tree. That’s how we know the tree is there” (p. 133).

Direct Realism (2) Mind <= Physical World

Cartesian Theological Realism (1) Mind => (Systematic Doubt) => Cogito => God => (Non-deceiving God) => Physical World

Cartesian Theological Realism (2) The Evil Demon Argument Cartesian Argument for the Cogito

The Brain in a Vat Thought Experiment INPUTS => => OUTPUTS

Idealism (I) Reality is constituted entirely of minds and their ideas, which are mental representations of objects.

Idealism (2) Mind => (God) => “Physical World” (Phenomenal World)

Objections to Subjective Idealism Runs contrary to experience (e.g. of dishwashers) Have to assume, or prove, the existence of a non- deceiving God Makes scientific, artistic, or political practice unintelligible, e.g. cannot distinguish between appearance and reality  ( video) video

Vision and the Brain Perception isn’t a passive process: “The mind does not simply record what passes before it; instead, the mind actively interprets experience according to certain built-in principles. Therefore, what we think of as ‘simple’ perception is actually the result of a complicated interpretation of the sensory data” (p. 134).

The Commonsense View (1) “We have experiences such as ‘seeing a tree’ or ‘hearing a cricket’ because our bodies interact with a physical world that includes things like trees and crickets. The world impinges on our sense organs, causing us to have experiences that represent the world to us in a fairly accurate way. The physical world exists independent of us—that is, it would exist even if we didn’t exist, and it continues to exist even when we are not observing it” (p. 137).

The Commonsense View (2) Mind <= Brain <= (Bodily Interaction) <= Physical World

Some Classic Cases of Perceptual Ambiguity Muller-Lyer Illusion Ponzo Illusion The Necker Cube Café Wall Illusion Ouchi Illusion Kanizsa Triangle E.G.Boring, “My Wife and My Mother-In-Law” Joseph Jastrow’s Duck-Rabbit Rex Whistler’s ( ) Reversible Faces The Thatcher Illusion

Muller-Lyer Illusion

Ponzo Illusion

The Necker Cube

Café Wall Illusion

Ouchi Illusion

Kanizsa Triangle

E.G.Boring, “My Wife and My Mother- In-Law”

Joseph Jastrow’s Duck-Rabbit

Rex Whistler’s ( ) Reversible Faces

The Thatcher Effect/Illusion (An illusion of how it becomes difficult to detect local feature changes in an upside down face, despite identical changes being obvious in an upright face. It was created by Peter Thompson in 1980 and is named after former British Prime Minister Margaret Thatcher, on whose photograph the effect has been most famously demonstrated.)

Perception, Illusion, Color, and Context Beau Lotto is a British neuroscientist and founder of Lottolab ( a hybrid art studio and science lab. Here is a recent TED Talk he gave on perception, illusion, and context: w_we_see.html

Objections to the Commonsense View “Dissolving World” thought experiment (pp ) Brain in a Vat revisited

Alex Byrne, “Is Snow White?” Alex Byrne teaches in the Department of Linguistics and Philosophy at MIT. Many of his writings are available through his website: s.html

Color Realism vs. Color Idealism Color realism = colors exist in the world independent of human perception and so “objects typically have the colors that they appear to have: lemons are yellow; blood is red; snow is white” Color idealism = colors exist only insofar as they are perceived by human beings

Five Arguments against Color Realism The argument from variation The argument from microscopes The argument from other species Colors as powers Colors as ways of changing the light

Three Arguments for Color Realism Color idealism violates rules of our language Color idealism is self-undermining The case against color realism is a little too strong