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13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism

[our confidence in perception is undermined by illusions]

18 ideas
Illusions are not false perceptions, as we accurately perceive the pattern of atoms [Epicurus, by Modrak]
Epicurus says if one of a man's senses ever lies, none of his senses should ever be believed [Epicurus, by Cicero]
A false object might give the same presentation as a true one [Arcesilaus, by Cicero]
Most supposed delusions of the senses are really misinterpretations by the mind [Lucretius]
Every true presentation can have a false one of the same quality [Cicero]
The same oar seems bent in water and straight when out of it [Sext.Empiricus]
The necks of doves appear different in colour depending on the angle of viewing [Sext.Empiricus]
The same tower appears round from a distance, but square close at hand [Sext.Empiricus]
If we press the side of an eyeball, objects appear a different shape [Sext.Empiricus]
Only judgement decides which of our senses are reliable [Descartes]
We correct sense errors with other senses, not intellect [Mersenne on Descartes]
It is prudent never to trust your senses if they have deceived you even once [Descartes]
The senses can only report, so perception errors are in the judgment [Gassendi on Descartes]
If pain is felt in a lost limb, I cannot be certain that a felt pain exists in my real limbs [Descartes]
It is possible that we could perceive everything as we do now, but nothing actually existed. [Berkeley]
Examples of illusion only show that sense experience needs correction by reason [Hume]
Psychologists say illusions only occur in unnatural and passive situations [Lowe]
Illusions are not a reason for skepticism, but a source of interesting scientific information [Sorensen]