Unit 2 WoK 1 - Perception
Russell Reading - Appearance and Reality The Russell document provides a basic framework for looking at the limitations of our senses. In small groups, discuss and record what KQ are raised in pp. 9-12 of the document. Be prepared to share a quote that illustrates or supports each KQ you list. Plato sees the cave as the world of our senses. Is Plato s conception of this world positive or negative? Does Russell agree or disagree with Plato s assessment of the sensual world (would he agree that it is a cave?) Given the flawed nature of our senses, if someone were born with no senses, what would it be like to be that person? Would Russell and Plato agree on the answer to this question? If you had to give up one of your senses, which would it be? Why? Which AoK is impacted most by Russell s observations?
I. What is perception? The World Knowledge A. Sensation B. Interpretation
II. The philosophy of sense perception A. The rationalist tradition 1. Plato
Plato s theory of knowledge - The broken line Ideas (the forms) : The Things as they are, Truth intelligible World The visible/ sensible world Mathematical objects : theoretical science Physical objects : beliefs about physical things (perception), empirical science Images, shadows : opinions, illusions, imagination
2. Rene Descartes
B. Empiricism 1. John Locke
John Locke from, An Essay Concerning Human Understanding Let us then suppose the mind to be, as we say, white paper, void of all characters, without any ideas; how comes it to be furnished? Whence comes it by that vast store which the busy and boundless fancy of man has painted on it with an almost endless variety? Whence has it all the materials of reason and knowledge? To this I answer, in one word, from experience. In that all our knowledge is founded; and from that it ultimately derives itself. (accessed on 9.29.13 at http://www.cla.calpoly.edu/~rgrazian/docs/courses/230/instruction/handouts/lockeideas.pdf)
Locke s primary and secondary qualities
2. Berkeley
2. Hume
All know can be expressed by either analytic or synthetic propositions Analytic propositions - a priori, true by definition, negation result in contradiction (a married bachelor!) Synthetic propositions - a posteriori, derived from sense data
The problem of induction We observe that x follows y so we reason that y causes x But if there were no causal relationship we would still perceive x following y Therefore it is impossible, based on sense data, to distinguish seriality from causality
The World Knowledge = For perception to be certain, we need to establish that material objects in the world directly cause our perception of them...... but Hume maintains that this is impossible
III. The Mechanics of sense perception Class activity
IV. Illusion and Interpretation The Blind Spot, or, I m not making this up but your brain is! Blind spot test
IV. Illusion and Interpretation Figure and Ground
Context
Expectation
Visual grouping
Group Activity In six groups of 5-6 examine the four assigned illusions (A = 24, 6,12, 18) (B=2, 7, 13,19) (C = 3, 8, 14,20) (D = 4, 9, 15, 21) (E = 1,10,16, 22) (F = 5,11,17, 23) Play around with each illusion and discuss what is going on with your group Fill out the Perceptual Illusion Template based mainly on your observations (not the explanation provided.) Choose the illusion of the four you find most interesting. Your group should prepare a presentation on this illusion for Friday. Your presentation should include the material from the template, plus the following items: Why you found this the most interesting of the illusions How the principles behind this illusion might be similar to real world situations involving perception What knowledge questions are raised by this illusion (be more specific than To what extent can we trust our senses )
V. Theories of the relationship between reality and sense perception A. Common Sense Realism =
B. Scientific Realism My scientific table is mostly emptiness. Sparsely scattered in that emptiness are numerous electric charges rushing about with great speed; but their combined bulk amounts to less than a billionth of the bulk of the table itself. Notwithstanding its strange construction it turns out to be an entirely efficient table. It supports my writing paper as satisfactorily as table No. 1(common sense realism); for when I lay the paper on it the little electric particles with their headlong speed keep on hitting the underside, so that the paper is maintained in shuttlecock fashion at a nearly steady level. If I lean upon this table I shall not go through; or, to be strictly accurate, the chance of my scientific elbow going through my scientific table is so excessively small that it can be neglected in practical life.... There is nothing substantial about my second table. It is nearly all empty space - space pervaded, it is true, by fields of force, but these are assigned to the category of "influences", not of "things". --Arthur Eddington, 1927 (Accessed on 10.15.13 at http://www-history.mcs.st-and.ac.uk/extras/eddington_gifford.html)
C. Phenomenalism The criterion which we use to test the genuineness of apparent statements of fact is the criterion of verifiability. We say that a sentence is factually significant to any given person, if, and only if, he knows how to verify the proposition which it purports to express that is, if he knows what observations would lead him, under certain conditions, to accept the proposition as being true, or reject it as being false. --A. J. Ayer in Paul Velasquez Philosophy: a Text with Readings (Accessed on 10.15.13 at google books)