Richard asked:

More and more I keep hearing the phrase "perception is reality." On the surface this is an interesting
thought. In a very shallow way it may even have some validity. I have argued that if this statement is
true then a pencil really does bend when placed in a glass of water. I have noticed many of my
students are starting to act as if this statement is valid. Would you offer some thoughts or ideas on to
counter this statement.

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Firstly, it seems that your students have very grand ideas of themselves if they think that the world
consists of what they can perceive. Already Bishop Berkeley thought of this problem when he asked if
a noise in a forest existed if there was no one there to here it. You could ask your students if they
think that the world does not exist when they are asleep? Or if they don´t think anything beyond the
horizon exists.

At another level there are ideal objects like the numbers. Take the number two for instance. How can
any one perceive it? Sure we can look at two dogs or two houses, but where is the two itself? For
some people with 'discalculi' this is a real problem. The same goes for objects like democracy or
constitution. A really mind-boggling concept is the concept of "me". I am convinced it exists, but what
is it?

Fredrik Robinson

A simple visual perception can't amount to knowledge, without tactile experience from which we come
to know that a pencil is not made of the sort of stuff that bends in water. Our perceptions allow us to
function in what we regard as the real physical world. Visual perception alone is not functionally
sufficient for physical interaction with what seems to be external.

Even Berkeley, who thought that visual and tactile ideas were non-identical, wouldn't say that that is
all that is needed for reality.

I wonder what sort of things your students are doing.

Rachel Browne