about colours

© giovanni casu, 2016

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About Colours :


Example n°2: neon gelb 808.

Giovanni Casu 2014.

Acrylic on canvas, 40 cm x 60 cm.




This work is intended as an example of something that makes a special kind of phenomenological experience possible. This example enables the viewer to sense or experience a particular kind of blueish-violet colour as a consequence of the presence of a particular set of perceptions, especially the presence of the colour called Neon Yellow 808.


This work is inscribed in the context of the projects of the Museum of Colours and I would like the viewer to take it as a preliminary experience, in order to extend his/her own understanding of the following considerations. The following considerations are definitely part of the work and are necessary to its functioning.


What can we say about the nature of colours by looking at this example? Experiences of this kind are commonly interpreted and classified by contemporary viewers as “illusion” or “optical illusion”. This assumption implies that something appears to be there, but is not. Following this common sense approach, there is a parting of what-is-really-there and something that seems to be there, but is not.

This means that the concept of “illusion” presupposes that there is a true world, and that it obeys to certain rules: the phenomena that do not respond to these rules are eventually defined as illusionary. Continuing this line of thoughts, the real world is our everyday world, and it is also supposed to be colourful, full of objects, people , hopes, wishes, tennis balls, facts and so on.

In our days, the rules (or theoretical models) that discriminate what is real from what is an illusion mainly stem from a scientific understanding of the world.

Science describes colours as deriving from “light” or something created from electromagnetic waves interacting with the eyes and the retina. This approach has been more and more thoroughly developed following scientific discoveries, leading up to the late neuroscientific analysis of these phenomena. In the trial to verify what happens inside the brain, neuroscience is confronted with the simple fact that there are no colours inside the brain, but “only” biological circuits, structures, micro-structures, chemicals, electric activity and so on.

Neuroscience tries to explain or solve this impasse in several ways. David Chalmers (1) ( reported here as a symptomatic example of this theoretical embarrassment) proposed the concept of “hard problem” in neuroscience, claiming that the problem of experience will “persist even when the performance of all the relevant functions is explained”(1). From a neuroscientific, or tout-court scientific, perspective the basis of visual-sensory perception are qualia. Qualia are simple phenomena of something…like colours, but also the simple scent of a rose or the texture of a smooth surface. From a neuroscientific point of view, the nature of qualia remains a mystery and science has left the question opened (2).

It appears, then, that the scientific approach has not yet delivered a satisfactory and comprehensive explanation of what colours are. But if, for the sake of curiosity or intellectual appetite, we try to develop a coherent theoretical reconstruction of these phenomena (in keeping with the results of the scientific approach) we can contend that at least two kinds of reality seem to exist. The first is a hypothetical one that science tries to define through theories, hypothesis, and experiments. This reality involves molecules, micro particles, electromagnetic waves, quantum stuff, light, the visual cortex, V1, V2, …V4 brain areas etc. The second reality is our everyday reality, the one you are probably living in right now. At this point, the appropriate question seems to be “how can we conciliate these two worlds? (I mean, in such a way that the reality of “colour” is not split into 2 incoherent realities or approaches). G. Harman´s The third table. (3) addresses this kind of question.




The philosopher Wilfrid Sellars (4) suggests that the basic flaw in the empiricist approach is to believe that the two worlds (the scientific one and the phenomenological one) have different constituents, that the two worlds have a different “nature”. This misunderstanding is based on what Sellars calls the “Myth of the given”. The Myth of the given is the assumption that there is some basic data offered to humans in a kind of naked and innocent way, available to human perception without a conceptual structure. And this “naked” data are, for example, colour perceptions.

For Sellars the colours that science describes and the phenomenological colours described as everyday experience “contain” the same constituents, that is to say that both are theoretical constructions that require a complex conceptual machinery to be there and to exist. To put it as simply as possible, to build both of those realities we need a complex semantic structure and inferrential language games. Without this structure even a simple experience is an illusion, or better, it is a blind experience, not an experience at all. This means that we cannot select one approach or the other without losing a fundamental aspect of what a colour is. Science creates theoretical models that can be applied to observation, and phenomenological reality is tangled up with conceptual content in an inseparable way. The only solution seems be that of adopting a synoptic vision.

The violet colour we see is produced by our conceptual machinery as reality, and, as such, it can be related to the other colours that have chemical origin . So the origin of this reality is a theoretical construction that implies the hypothesis of something in it-self unreachable, colourless and meaningless. This conceptual entity has to be related to the experience of “real colours, illusions or hallucination” to complete the tryptic of the reality of colour: 1) a hypothetical, unverifiable, not directly approachable and metaphysical reality – allow us to say - in it-self, 2) …a culturally and genetically developed conceptual machinery, 3) …and the phenomenological reality which we inhabit as a consequence and result of the first two.

This example tries to convey the concept of these 3 worlds as a necessary tryptic of the reality of colour in - I hope - an interesting way.



1) http://en.wikipedia.org/wiki/Hard_problem_of_consciousness and David J. Chalmers (1996). The Conscious Mind: In Search of a Fundamental Theory. New York and Oxford: Oxford University Press.)

2) C.Koch. The Quest for Consciousness: a Neurobiological Approach, Roberts and Co., (2004). P.260.

3) G. Harman .The third table. dOCUMENTA13. n^85.. Hatje Cantz.


4)W. Sellars. Science and Metaphysics. 2_II)Empiricism and the Philosophy of Mind. 2_III)Meaning as functional Classification. 1973. Archives of scientific Philosophy.














Katsushika Hokusai: 'The Blind Men and the Elephant.' Japanese woodblock print, 1817.