Austin - 3 and 5: Argument from Illusion

The argument from illusion tries to show that what we directly perceive is ALWAYS sense data (and never material objects):

In illusion cases, what we directly perceive is sense data.
In non-illusion cases, what we directly perceive is the same as what we directly perceive in illusion cases.
So in ALL cases what we directly perceive is sense data.

Austin tries to show that this argument is based on a series of mistakes.

These summaries and problems deal with Chapters 3 and 5 of Austin's Sense and Sensibilia (New York, Oxford University Press, 1964). These exercise materials are copyrighted (c) 1998 by Harry J. Gensler but may be distributed freely.