Lecture 2: 27/10/2010 Senses, perceptions and illusions: How the “Way of Opinion” led the way

Parmenides believed that all that exists already existed and that nothing can come from nothing.  He believed that change is purely illusory and our senses are misleading.  He outlined these thoughts in his poem, The Proem which is divided into two parts, the Way of the Truth and the Way of Opinion, fragments of which have been preserved and quoted by various sources.  Parmenides believed that reality and our perceptions of reality are different and this influenced Plato which is clear from his Simile of the Cave.  Since the pre-Socratic era, the notion of reality and perceptions has been visited time and time again by philosophers and examples include the “brain-in-a-vat” analogy by Putnam (a theory even explored in the 1999 film, the Matrix), Locke’s theories of Human Understanding, and works by Descartes and Berkeley, to name but a few examples.  Permenides may have begun by wondering about the nature of the world and arrived at a conclusion of distrust and questioning of human perceptions, but modern philosophers maintained this questioning while exploring themselves and what it is to be an individual.

Even as a child I remember asking myself and others the simple question “how do I know that the colour red that I see, is the same red as you see?”.  This question outlines the very basics of the problem of perceptions and trusting our senses.  Even if we could see through the eyes of another, how do we know that what humans perceive is the absolute truth?  There is no answer to this, but as scientists we can test hypotheses and look for reproducibility in our experiments to gain trust in their results and accept them as the truth and as fact: However if we cannot trust our senses, even if we obtained a perfectly repeatable results, how would we know if this is the truth?  What is the truth?  The truth appears to be only something we can perceive.  If there are no absolute facts for sure, then truth is merely subjective and leads us to believe that everything is relative, as the sophist Protagoras stated “man is the measure of all things” and if this is true we must question everything as we can be sure of nothing, but we will never have any answers for sure, just more questions.