What’s in a Rainbow?

The image of the rainbow is conventionally seen in Judaism as expressing hope: hope for the future of humanity and of nature itself. Its appearance in the Biblical text – Genesis 9: 12-17 – follows the well-known story of Noah’s survival of  forty days and forty nights of rain, a flood that overwhelms everything that God had created: flora, fauna, humanity itself.  The storytellers of the Bible portray the destructive aspect of divinity as co-existing with the creative element within the divine.

The character ‘God’ expresses a hope – it is described as a ‘covenant’ - that such innate destructive energy will never again win out over the life-giving creative aspects of ‘God’. This is what one might see as the pious hope of the storytellers – the rainbow is to be the reminder that destructiveness will not have the final say. Perhaps this is as much a hope about human destructiveness as so-called divine destructiveness – for the storytellers of Genesis certainly saw these energies as co-existing within the human heart as well.  

What is a rainbow? We now know of course that it is a refraction of light through water drops, which breaks up white light so that we see the various colours within it. And we might recall that we owe this understanding about the rainbow’s colours to Sir Isaac Newton who, from 1665, performed experiments with a prism which produced a spectrum in which he identified for the first time a full range of colours. (Actually a book was published the year before that, by the Anglo-Irish physicist Robert Boyle, describing the five colours of light). But we know how many colours Newton discovered - seven.

I don’t know if children still learn these colours as I did in school, with a mnemonic, Richard Of York Gave Battle In Vain: red, orange, yellow, green, blue, indigo and violet. And I don’t know if similar mnemonics exist in other languages? But the seven colours of the rainbow is what used to be called common knowledge. However one of the problems with so-called ‘common knowledge’ – what we think we know, what we think of as true - is that, more often than is comfortable for us, it turns out to be wrong. Or at least, it turns out that our certainties are either false, or much more complex than we like to think.

In this example – the rainbow – what happened when Newton conducted  those experiments was that he did indeed discern a spectrum of colours within the water droplets - but there were only six of them. The colour he eventually called ‘indigo’ didn’t exist – there was a plant that grew in India  called indigo, from which a deep-blue dye could be produced, a plant that had just begun to be imported into Britain by the East India Company early in the 1660s, and Newton borrowed the word ‘indigo’ to describe a seventh colour existing between blue and violet – but it was a colour he wanted to see, not that he actually saw.

But why would he do that? Why would he make up, invent, a new colour? One might fleetingly imagine that perhaps he had shares in the East India Company: maybe he wanted to boost sales - ‘Here’s the rainbow, and look, we have my newly discovered  ‘indigo’ within it!’ – so perhaps a form of what we’d now call ‘product placement’?  Probably not.

But what I do know is that Newton needed a seventh colour because, and this is the point, he wanted to harmonise his new discovery with other aspects of harmony in the world around him: first, he wanted to link this natural harmony of the structure of light with the harmony of the classical musical scale of Western culture, the seven notes (do, ray, mi…) used in European and Mediterranean music; and, secondly, he wanted the structure of light to be in harmony with creation itself – because in his view seven was the great mystical number underpinning the creation of the world: in the Biblical story, the Biblical myth, that majestic piece of poetry that opens the Bible, God’s creation of all that exists unfolds in seven ‘days’, seven stages.

Newton was a mystic as well as what we now call a ‘scientist’ - the word ‘scientist’ by the way wasn’t coined early in the 19^th century; until then they were ‘natural philosophers’ – and his mystic philosophy held that the number seven had special and cosmic significance. (Remember that at that time only seven planets were known to exist in the solar system). Newton wanted his discovery to mesh with creation itself; and he believed he’d revealed something fundamental about the structure of nature itself, these seven colours within light. So he inserted a colour, indigo, that didn’t exist, into his spectrum; and this wonderful bit of creativity, grandiosity, chutzpah – call it what you want – became the basis for the way a whole culture then saw the rainbow, sees the rainbow.

And we, the inheritors of this piece of Newtonian scientific myth-making, mischief-making - call it what you want – still speak about (and see) what Newton thought he saw: the seven colours of the rainbow. In other words, we project onto the rainbow what our culture has taught us to expect to see there.

And we will insist when we look at a rainbow - and we do look because it is a kind of marvel, even though we know it’s only the sun on drops of water – we will insist: ‘oh, there it is, squeezed somehow between blue and violet, there’s indigo’. We do see it - or rather we create it in our mind’s eye and with our imagination - because we have been told it’s there.

That’s the power of suggestion - even though there are other cultures, in Africa, or amongst native Americans, who traditionally see four or ten colours when they look at a rainbow.  (I’ve noticed, en passant, that in the LGBTQ+ Pride flag, the rainbow only has six colours, that indigo is missing).  

But what’s the significance of all this?

When I reflect on Sir Isaac Newton’s discovery of - invention of - the seven colour rainbow I find that it raises for me a large question. It’s a psychological question, a political question, an interpersonal question about relationships, it’s a spiritual question, a social question – in fact it’s a question which is relevant to almost every aspect of our lives: how often do we see what we expect to see, and not what is actually there? How often does what we are conditioned to see dictate what we see? How often does what we are taught to see – by our teachers, our leaders, our rabbis (dare I say it)  – how often does what others say is the case blot out, or obscure, or distort what is actually there?

To see the world as it is, rather than as we’d like it to be, is not straightforward – it can be too painful to see what’s in front of our eyes: to see the foodbanks, the homelessness, the systemic injustices and discriminations, the vast disparity between the wealthy and the impoverished in our society, to see Antarctica melting and the sea levels rising and the empty reservoirs. We may well not want to see what is in front of us.

But I believe that Judaism tries to help us, it encourages us, to see what is there, in front of our eyes – at their best all the major religions are a lifelong education in helping us towards seeing truly and deeply, helping us not to be fooled by, or seduced by, illusions and delusions and falsehoods: economic thinking, political thinking, social attitudes, popular culture, are filled with false ways of seeing or thinking. And there are plenty of falsehoods spun by religions as  well.

But there’s one phrase that comes up time and time again in Jewish liturgy and in the psalms of the Bible – “Open our eyes” – we say it over and over in one form or another because it’s a profound and abiding human wish to be able to distinguish between truth and falsehood, truth and propaganda, truth and lies.  And maybe we say it so often because there’s a recognition that it’s so hard to do - to see clearly.

And now the paradox. Yes, Judaism is an ongoing project of helping us to see life more clearly, more truly - Freud called this the ‘reality principle’ - to see what is really there, what’s really going on, to strip out false-seeing; but Judaism also teaches us to try to see what is not there, what we wish to be there, like Isaac Newton. It teaches us to see, to imagine, to create – first in our mind’s eye and then in reality – what does not yet exist: a world of justice, a world of compassion, a world of peace, a world of generosity and mutual respect. So Jewish seeing is a dual project – to see what actually is, and to see what could be.

Indigo represented Newton’s profound wish for a world of harmony. He helped us to see it, to imagine it, in nature even if it’s not actually there. What Judaism teaches is analogous to that: it teaches us to shine light, yes, on what is actually there, including the flaws and the failures; but it is also teaching us to see, to keep alive, the picture of what could be there. You can’t build a better world unless you can see both what is in front of your eyes and what is not yet in front of your eyes. ‘What is’ can be transformed into ‘what ought to be’ – that is how Jewish hopefulness works, it’s a Messianic hopefulness. The world can be changed for the better – creativity can win out over destructiveness - but it can’t be changed until we look clearly at what actually exists in front of our eyes.

[based on a sermon given at Finchley Reform Synagogue, London, on 29^th October, 2022]