dong20 said:
But you can see it so it must exist.
Absolutly not!
A magician does tricks, by your logic, when he saws a woman in half, she really is in two pieces, but she isn't, it is an illusion.
Just because you can "see" something, doesn't mean it exists, there is a very real possibility that you are mistaken in what you see. Ever seen the mountaineer sketch in Montey Python? The John Cleese character has double vision, and thinks that there are two peaks of Kilamanjiro, just because he saw them, does that mean that there really are?
A shadow is an effect, as I said, caused byh the way the light does not hit an area, but hits surrounding area due to an object being in the way of the certain light-less area and the light source. We label this phenomenon a "Shadow" - it has no physicial existence, it is a phenomenon.
It has width, it has length and it can vary with time so by your terms it must have depth.
What terms?
No, it doesn't have depth or width or height in the traditional sense. As I said, it is a phenomenon, you can measure the area in which it is takeing place, that has a width and a height, but you are measuring a section of another object, for example, the pavement, you are not measureing a physical entity known as a "shadow".
So, the removal of something physical results in the creation of something else that is visible and interactive but doesn't really exist in the physical realm yet it clearly does.
Ah-ha! Now we get into Ontology, a subject I quite like.
LADIES AND GENTLEMEN, SCIENCE HAS LEFT THE BUILDING!
Please welcome our new guest, Metaphysics! Metaphysics - I hear you are a form of Philosophy, am I correct?
Metaphysics - Yes SomeGuy, you are!
Its an itneresting idea, that you can have physical objects, such as you, me and the chair I'm sitting on, but also non physical objects such as maths, righteousness and yes - shadows.
Plato outlined a theory which explained this in his
Theaetetus - he devided the world into two parts, the physical, and the mental. The physical contains exactly what you expect, physical objects. The mental contains "forms" which we use as a sort of "name tag" for physical objects and also as abstract things in their own right.
Example, I am sitting on a chair, that chair is a physical object, certainly but we identify it by reaching out to a form of "chair-ness" to label the chair by. If we didnt have these forms as guildlines, how would he know what to call things?
Imagine
If you had never seen a shadow and didn't understand the variable nature of light and I described a shadow in the terms above, you would probably think it was preposterous as it would be beyond rational understanding, you would therefore almost certainly deny it's existence.
To me that is exactly what you are doing here; by denying the existence of a theory because it is a) Beyond your understanding and/or b) Outside your physical 'reality' or experience and sounds riduculous.
Are you getting me confused with somebody else? I am argueing
FOR the theory!
I simply picked on your point because shadows are not physical entities, they are phenomenon.
