Colour Fundamentals: Escaping the Paralogisms

Two facts about colour strike me as obvious, profound, overlooked, and philosophically puzzling.

1. Colour is Real It is literally true to say that some of the squares above are red and others green. Moreover, red and green are stable properties of these objects. Never mind how ‘X is red’ is to be analysed: whether in terms of dispositions, relations, physical properties, simple properties, whatever. Whatever way you analyse colour, it had better be true that it is a real property of things in the external world.

Why?

(a) Because colour supports inferences such as ‘That mango are red. That mango is ripe. Therefore I should raise my expectation that red mangoes are ripe.’ How could such an inference be correct if red were not a property of the mango, not just my mind? 

And (b) because many animals (including humans) make such inferences instinctively. Evolution couldn’t have subsumed colour under our normal inductive inference patterns without some support from the world, i.e., from the nature of coloured things.

2. Colour Reveals Its Own Nature Look at one of the bluish squares above. Does it show a touch of green? Assuming you are a trichromat, you have an opinion. But you must concede you could be wrong about the colour of the square: maybe the lighting is funny.

But here’s a different question: Is the apparent colour of the square greenish? More didactically: Let C be the colour the square appears to you to be: is C a greenish hue? About this, you can’t be wrong. You’ve experienced C, you know. If I experienced C, I would have to agree with you.

What I just said is a bit tricky, but I won't say more to try and persuade you, except to repeat myself. You can’t be wrong about the nature of a colour you have experienced—about the nature of that colour property. Of course, you may well be wrong about some thing that looks that way, specifically about whether that thing really is that colour.

Here’s what’s odd. If colour is a real property of things, how can you be so certain about the nature of the property. Consider a parallel. Water is a real property of things. But you can’t be certain of the nature of water just by looking at it. You can't be certain, just by looking at something that appears to be water, whether the water property (which appears to belong to the liquid you are looking at) has composed of hydrogen as a component. Similarly, if colour is (say) a physical reflectance, how can I know what its components are? How then can I know that turquoise has greenish as a component?

Traps Each of the above suggests a paralogism. Colour is real, so it is objective. Colour is knowable with certainty, so it is subjective.

Escape The problem is similar to the one that inspired Kant’s theory of space and time. How, Kant asked, can you be certain of the nature of space—e.g. that it is three-dimensional—if it is true independently of you that things are arrayed in space? Kant’s answer. Space is the form of outer intuition: you know its properties simply by having “outer intuition.” (Note, by the way, that regardless of what Kant himself may have thought, this does not imply that space is unreal.)

I want to propose that some features of colour are formal in exactly the same way.

Here’s the view. Colour vision reveals certain real characteristics of things. But colour experience is a "code", a sensory “language” made for the presentation of these characteristics. You are looking at an olive, let us say: it looks greenish, somewhat yellowish, and dark. Think of this look as simply a specification of a real property attributed to the  olive. Colour vision codes up that property in terms of greenish, yellowish, and darkish components. 

In this way of thinking, you cannot be wrong about the chromatic components of an experienced colour. These components are the code that colour-sense employs to specify colour. Yet this is compatible with the colour being real. Kant said about space that you know nothing about spatial relations beyond that which is implied by the way your senses represent them. Thus, it is true and also certain that squares possess two axes of symmetry, and are in this way closer to ellipses than to circles. In the same way, the senses tell you nothing of the nature of colour beyond that which is implied by how you sense it. Thus, it is true and also certain that turquoise is bluish and greenish, and is in this way more similar to emerald than to crimson.

Can you, dear reader, think of another way to evade the paralogisms of Colour Realism and Colour Certainty?