“There is a book on the table. The book is brown. I will accept the book exists. But does the colour brown exist?”
Brown is a wavelength. White light bounces off the book. The characteristics of the book absorb certain wavelengths. What is not absorbed is reflected. Let us call this isolated, reflected wavelength (low-intensity light at 600 nanometres) which reaches our eyes “brown”. The eyes, which are receptive to wavelengths, transmits that information from the retina down the nerves to the brain where it is equated to “brown”.
You see the book. I see the same book. The colour which is reflected corresponds to “brown” in your vocabulary and my vocabulary. But whether we see the same colour in the same manner does not matter. As long as we are talking about the same “thing” is all that is important.
In this sense, we have isolated the property “brown” to be the wavelength and given it this agreed-upon name. The wavelength exists as light, as energy. I would say “yes”, it physically exists.
Naive realism holds that its philosophy of perception can be summed up in the following way:
- There exists a world of material objects.
- Statements about these objects can be known to be true through sense-experience.
- These objects exist not only when they are being perceived but also when they are not perceived. The objects of perception are largely, we might want to say, perception-independent.
- These objects are also able to retain properties of the types we perceive them as having, even when they are not being perceived. Their properties are perception-independent.
- By means of our senses, we perceive the world directly, and pretty much as it is. In the main, our claims to have knowledge of it are justified.
I am satisfied with Statements 1 and 2.
But I have trouble with part of Statement 3 – “The objects of perception are largely, we might want to say, perception-independent”. “largely” seems to suggest that there is something that is perception-dependent.
The concept of object-property in Statement 4 is also problematic. Whether an object has properties or not is unknown.
And Statement 5 also suggests that perception is an unproblematic or non-existent medium. Direct perception must mean without needing sense faculties. A damaged eye or clouded view must necessarily suggest that the medium is not perfect and therefore not direct.