Generally speaking, most of us rely on Common-Sense Realism, in which we accept that our sensory apparatuses (i.e. eyes, nose, tongue, finger tips) are mostly straight-forward and passive, giving us an accurate picture of reality. Most of us would agree that our senses play a critical role as a source of knowledge. Science, for instance, traditionally relies on observation to collect the empirical data that leads to scientific knowledge.

In practical terms, we seem to be able to agree to a great extent on the reality of the world that comes to us through our senses.


The traffic light is evidence for how much faith we put into the reality of the world as perceived by others through their own eyes. We literally stake our lives on this belief. Some people subscribe to the philosophical school known as Empiricism, in which all knowledge is ultimately based on perceptual experience. There are some problems with this position though. With examination, our perception of the world is clearly limited by our apparatuses (our sense organs) and what we do perceive is often determined by interpretation of one kind or another.


Consider the following quotations. As you do so, try to understand exactly what was meant by the quotation and what the implications are if such claims are true.

  1. It’s not what you look at that matters, it’s what you see (Henry David Thoreau)
  2. Two thirds of what we see is behind our eyes (Chinese proverb)
  3. A fool sees not the same tree as the wise man sees. (William Blake)
  4. The greatest calamity that can befall people is not that they should be born blind, but rather that they should have eyes and yet fail to see. (Helen Keller)
  5. Whilst part of what we perceive comes through our senses from the object before us, another part (and it may be the larger part) always comes out of our own mind. (William James)
  6. Things do not seem the same to those who love and those who hate, nor to those who are angry and those who are calm. (Aristotle)
  7. The greatest thing a human soul ever does is to see something, and to tell what it saw in a plain way… To see clearly is poetry, prophecy and religion - all in one. (John Ruskin)
  8. It is only with the heart that one can see rightly; what is essential is invisible to the eye. (Antoine de Saint-Exupery)
  9. Every man takes the limits of his own field of vision for the limits of the world (Arthur Schopenhauer)
  10. If the doors of perception were cleansed, everything would appear to man as it is – iinfinite. (William Blake)
  11. You can’t depend on your eyes when your imagination is out of focus. (Mark Twain)

Discussion Posting

  1. Write a thoughtful response (around 250-300 words) to the task below in your class discussion page in the toolbar on the left.
  2. Comment on at least two other responses. One of your comments must be to a response without any comments. Make this something more substantial than, "Great Response!"

  • Choose one of the quotes above (from our class discussion) and explain A) what you think the author intended to say and B) the implications of this truth on our daily lives.

Lesson 1: Are our senses straight-forward and passive?

Lesson 2: What you see is what you get?

Lesson 3: Waht yuo see is waht you gte?

Lesson 4: Selectivity of perception

Lesson 5: It's all in your head



I drive to school in Turkish traffic every schoolday. So far so good. This could be taken as evidence that perception does work as a Way of Knowing. Is Perception an accurate way of knowing (Correspondence)? Is Perception a useful way of knowing (Pragmatic)?

The Problem with Perception is that interpretation plays a role in what we perceive.

This can be due limitations of our senses, our brain's fumbling interpretation on what our senses give us, our previous understanding of the world (culture, paradigms, personal experience) coloring what we perceive, our brain's conditioning, or a number of other issues.

ToK LInks: How does Perception link to other AoKs & Woks

Perception WOK Vocabulary:

Common-sense realism, Empiricism, Figure and ground, Phenomenalism, Scientific realism, Sensation, Visual agnosia, Visual grouping, Synesthesia

TOK Lexicon of all our vocabulary