Who Put The Colours In The Rainbow?

On the evolution of colour perception.

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The title of this latest post throws me back fifty years, to a time when I was standing on top of a sand dune in Bude, Cornwall, UK, leading a host of youngsters - and their mums and dads - in a chorus on a holiday beach mission.
Half a century on, this question has added significance for me as I ponder the depths of Quantum Mechanics and associated issues. It goes to the very heart of the assumed mechanistic nature of the cosmos, and the extent to which this reductionist view can, or cannot, address certain very obvious in-yer-face aspects of our physical reality.

That particular aspect was very much in-my-face yesterday as the sun broke through the clouds over Dartmoor to light up the winter showers with a brilliant burst of colour, from red right through the visible spectrum to violet. The same spectrum, in fact, as that revealed by Isaac Newton in the mid-1660s when he separated white light into its component colours with a glass prism for the very first time.

Those colours have, of course, been visible for far longer than that - since the dawn of man and millions of years before then for some other species; there’s no shortage of research literature documenting colour vision in dinosaurs. The question then arises: where did those colours come from?
This isn’t a trivial question. Unlike every other physical feature visible to mankind and other creatures, colours don’t exist as physical realities in their own right; they’re simply interpretations by our sensory systems - basically, eyes and brains - of a subset of the frequencies of electromagnetic waves which are all around us. But where did this ability come from? More to the point, where did colours themselves come from?

The stock answer, of course, is that, like every other aspect of our sensory system, colour perception evolved through random mutation and selection of characteristics which conferred competitive advantage in the deadly serious game of survival of the fittest: all good Darwinian stuff.
But this ‘explanation’ leaves out one crucial detail: how could random mutation possibly introduce into this evolution game a set of radically new features - colours - that aren’t even hinted at by aspects of the natural realm?

[Notice that we’re making a clear distinction between colour awareness and colour perception: there’s a distinct difference between being able to distinguish between different frequencies of light through sensory cells triggered by those different frequencies - and perceiving those different frequencies in the form our brain handles them - as distinctive hues from red through yellow and green to blue.]

Evolution, as identified by Charles Darwin, is essentially a fairly straightforward process, at least in principle: every living organism is subject to various environmental influences, which can at times give rise to minute variations in the genetic makeup of any of those organisms. If it so happens that such a mutation leads to a characteristic or trait which enhances reproductive or survival prospects then this new version of that organism will out-compete others of its original species in the reproductive stakes, and so become the dominant form of that species. Successive mutations over time can lead to organisms changing out of all recognition from the original form - evolution of a new species.

So far so good. This is all pretty elementary stuff, Evolution 101. Note, though, that it relies on random changes in cellular makeup or cell responses to stimuli, which are then selected by nature’s survival-of-the-fittest principle to progress along the upward evolutionary spiral. Any such beneficial random change aids in that progress.
So, for example, organisms containing cells which had become sensitive to light - the common frequencies of electromagnetic radiation - gained a tactical advantage over other organisms which didn’t have that sensitivity: the sense we now know as ‘sight’ was born. Successive, equally random, enhancements of this property led to eyes of various forms, from the multifaceted organs of insects to the orbs of numerous other species.
Over time, and equally randomly, some of those light-sensitive cells acquired a particular sensitivity to subsets of those electromagnetic frequencies. It would, for example, be advantageous to distinguish between the frequencies reflected off vegetation (which selectively absorbs some frequencies and reflects others - its own random mutation optimising its energy-gathering ability) and those reflected off rock. This would significantly improve identification of food sources. Likewise an ability to recognise light frequencies reflected off potential predators could significantly extend an organism’s life expectancy, and so also reproductive potential.

Again, so far so good. Evolution 102. But here’s where we seem to somehow slip from science fact into science fiction. Because here’s where we find that mechanistic process of random mutation somehow becoming imaginatively creative - and the idea of a random process demonstrating creative purpose is a contradiction in terms.

Let’s imagine we’re eavesdropping on a bunch of brain cells early in that evolutionary process. They’ve got a committee together to discuss a particularly knotty problem:
”Ok guys, so we’re now able to distinguish between different frequencies of light - electromagnetic radiation. This is pretty cool, because it means we can detect the difference between food and not-food, between something we can eat and something that might eat us. That’s all really useful.”
Murmurs of agreement from the committee.
”But all this data coming in is really tricky to handle. Sure, some of you guys can detect lower frequencies or higher frequencies, some of you can even get a different strength of signal depending on what the frequency is. But how can we analyse all this data in a meaningful way? How can we decode all these signals, all these signal strengths, in a way that we can act on without having to do a Fourier analysis every nanosecond?”
Long silence. Then a cell pipes up from the back row:
”I’ve got it! How about we use colour?!!”
Baffled looks all round. Then from the chair:
”Ok smartypants, so what is this ‘colour’ thing?”
“I don’t know exactly, it just sort of came to me. Maybe we could use, say, red for low frequencies, green for middling frequencies and blue for the top ones.”
”Sorry chum, you’ve lost me.” Murmur of agreement all round. “You’re going to have to explain to me about this ‘red’, ‘green’, ‘blue’ thing. What exactly are they?”
”Er, well” , in an embarrassed tone, “Not sure exactly. It just seemed like a good idea.”
”Sorry mate. We don’t do ‘good ideas’ here, we just do ‘random mutations’. If you can explain how random mutation can invent a radically new concept, I’m sure we’ll all be really interested to hear about it.”

And so it is. Colour was indeed a good idea - a brilliant idea - enabling assimilation of a mass of data instantaneously. But unlike detecting an on-off (light-dark) signal, or even different strengths or frequencies of signal, random mutation is not a process that could ever spontaneously engender in a brain cell a form of indexing for a radically new type of experience. Ability to detect a particular frequency, or range of frequencies, is one thing; attaching a totally new form of identification to that experience - colour - is something else completely. The latter is a creative act quite outside the remit of random mutation.

Not to put too fine a point on it, attaching a set of neural experiences to a palette of colours is a conscious act, an act of consciousness. The concept of colour isn’t some-thing that can be dreamed into existence by any mechanistic random process, it must necessarily involve a creative act of mind. Colour is the physical equivalent of an axiom, a self-evident truth: it’s not a necessary consequence of anything else - yes, it corresponds to different frequencies of electromagnetic radiation, but it’s not in any way predicted by the existence of those frequencies.
Colour stands in its own right as a fundamental concept; the idea of it coming into existence as a result of a mechanistic process just doesn’t stack up; how a random process could spontaneously originate the quality of ‘redness’ or ‘greenness’, experienced in that form by the brain, defies all reason.

It may be argued that, like other evolutionary processes, sensing of different frequencies would have developed gradually. This is almost certainly true, it’s also irrelevant here: the issue here isn’t that sensing itself, it’s about the way those frequencies are presented to the awareness of an organism (such as you or I). The choice of colour as a mechanism to represent frequency, when such a mechanism had not previously existed, doesn’t fit any plausible route of random mutation, however gradual - it’s apparently come out of nowhere. A mental mapping of electromagnetic frequencies into a previously nonexistent form of representation requires a random process that can spontaneously pull a totally new concept out of the hat, so to speak; this doesn’t appear to fit the Darwinian principle in any way whatsoever.

And colour-sensing isn’t just a one-off in the evolutionary playbook. We’re told that: “Color vision was so important that it evolved independently multiple times in the animal kingdom—in mollusks, arthropods, and vertebrates”. That’s an interesting take on things - an evolutionary step occurring because it was important. Doesn’t that imply some form of intention? Sure, if a random mutation confers significant benefits then it’s likely to become dominant in that genetic line - but it has to happen first, as a random event (so we’re told). How should we view a purportedly random event which dreams into existence a radically new form of mental experience - at least three times, quite independently - because it proves to be so very important?

We need to be wary here of falling into the twin pitfalls of circular reasoning and post-hoc rationalisation.
The first of these says: “Evolutionary advances are made through the process of random mutation; colour perception is definitely an evolutionary advance; so colour sensing is a product of random mutation; so evolutionary progress is (always) made through random mutation”.
The second says: “Random enhancements of physiological or sensory characteristics lead to increased success in an organism’s reproduction of its genetic makeup - more offspring with those same characteristics; colour perception definitely leads to greater reproductive success; so colour perception is a random enhancement of an organism’s sensory capabilities”. This is a classic example of the logical fallacy: ‘If A is true then B is true’ implies that ‘If B is true then A is true’.
It’s not enough to observe that colour-sense has the same evolutionary consequences as other evolutionary advances - that’s beyond question. The key question is whether it has the same causation as those other advances; that takes us way outside the remit of Darwin’s theory.

So where did colour come from?

Try this idea for size:
Colour is an intrinsic feature of the sensory makeup of the cosmos. This means it will be recognised by any organism embodying a spark of cosmic consciousness - such as us - once that organism has reached a level of evolution where it can receive through its sensory organs the differentiated frequencies of electromagnetic radiation corresponding to different colours.

This is fully consistent with observations by founding fathers of Quantum Physics: Erwin Schrödinger, who stated: “Consciousness cannot be accounted for in physical terms. For consciousness is absolutely fundamental”; and Max Planck, who said: “I regard consciousness as fundamental. I regard matter as derivative from consciousness…. Everything we talk about, everything that we regard as existing, postulates consciousness”.
Another leading luminary, at the forefront of research on Quantum Mechanics since his various ground-breaking papers on quantum nonlocality and entanglement in the 1970s, is Professor Henry Stapp, formerly of Lawrence Berkeley National Laboratory. In his book Mindful Universe (2007) he writes: “More than three-quarters of a century have passed since the overturning of the classical laws, yet the notion of mechanical determinism still dominates the general intellectual milieu”.

Consciousness is that property within each of us which experiences and interprets the plethora of sensory information presented to us by the physical realm around us. The relevance of colour to consciousness, in every aspect of daily life, needs no elaboration from me here.
We have only to look at pictures from the Hubble & James Webb space telescopes to see how deeply colour is ingrained in the fabric of the cosmos. Those pictures would be almost meaningless without colour. Many of those pictures have travelled for billions of years to bring us that detail; is it really thinkable that for all but the last few seconds in cosmic time these colours simply did not exist? Or have they just been waiting to be discovered? [Note that frequency shifting - ‘false colour’ - in some astronomical pictures doesn’t invalidate this point, it just shifts the baseline.]

On a more prosaic level, the senses of smell & taste and the finer elements of hearing similarly provide differentiation which is difficult to explain in Darwinian terms. (As an aside, it’s no accident that those finer elements of musical sound are referred to in terms of ‘tone colour’.) These, too, are elements of sensory experience more related to consciousness than to response mechanisms conditioned by randomness. Attempts to explain these evolutionary steps in terms of random mutations must inevitably come up against the question: “How did this concept originally come into being?”.

All, as we might say, food for thought (pun intended). Maybe that smartypants brain cell was onto something.

Next up

Next up is Why E = mc squared: Another first - the cause of this relationship discovered by Einstein but never explained, by him or anybody else, until now.
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