Hopefully by now, if you’ve read any of my previous eight blog posts on our wonderful, mysterious universe, you are beginning to appreciate how bizarre existence truly is. The universe is weird – nature is odd. Life is random and unpredictable (not always entirely, but usually impossible to completely pin down or understand). Everything seems to comes down to that Sartrean existentialist contingency – the dizzying idea that nothing is planned or predetermined; electrons appear and reappear at random, and we can only approximate where they might show up next in spacetime. Probability seems to reign supreme in how we make sense of what we experience.
The fine man
The legendary 1965 Nobel Prize-winning theoretical physicist Richard Feynman knew a thing or two about probability – he (along with Schwinger and Tomonaga) devised an ingenious method for explaining the bonkers behaviour of nature – and illuminated it beautifully in his charming (yet difficult to fully grasp!) book Quantum Electrodynamics: The Strange Theory of Light and Matter. His ‘probability amplitudes’ help to predict the likelihood of events at the quantum level – such as the quantity of photons which will bounce back off reflective surfaces such as glass (or more accurately mix with the electrons in the glass before a photon is sent back away from the glass). This interaction of light and electrons sees a photon begin its journey from a light source before it is recorded hitting both the piece of glass (or pieces of glass) and, upon travelling back, a photomultiplier.
In terms of partial reflection of light from a surface such as glass, experiment has shown us that an average of four out of every 100 photons are reflected back (4%) – and when you add more layers of glass to the experiment, the figure actually jumps to as high as 16%! As Feynman explains, we can’t determine why certain photons ‘decide’ to reflect and others don’t – we can only calculate the probability that some will. It’s strange behaviour which we simply can’t explain – but experiment shows it to be consistently true.
And Feynman was able to figure out the probability of these events simply by (get this!) drawing little arrows on a piece of paper. The length of each arrow is determined by the percentage chance of each stage of the event – so an arrow length of 0.2 represents the initial 4%; because 0.04 (4%) squared is 0.2. One then simply adds and combines the arrows for every extra sheet of glass (or stage of the total event) to amend the photon-hitting likelihood. The combination of the arrows gives the new probability. The direction one draws the arrows is key – and this is determined by a small stopwatch. It starts when the photon leaves the source and ends when it hits the photomultiplier. Whichever way the hand of the stopwatch is pointing, this determines the arrow direction.
Feyman endeavours to find the arrow whose square represents the probability of something happening. By simply adding up the sum of the various pathways, he arrives at the final probability amplitude – for every new piece of glass this would alter the probability of the event, and all the various ways it could occur.
To sum up Feynman’s grand principle then – the probability of an event is equal to the square of the length of an arrow (its probability amplitude). The general rule is – draw an arrow for each stage of an event for which you want to calculate the total likelihood (for events that can happen in multiple ways). Then combine the arrows. By hooking the head of one arrow to the tail of the next. The final connecting arrow is the one whose square gives the probability of the ENTIRE event.
QED probability amplitudes confirm that the angle of incidence (as expected) is where the most light is reflected off the glass – as this is the place where it takes the least time for the photons to return. The principle of least action is something I will go on to explore in more depth later.
But, seriously, apologies if I’ve just skipped over a bit of craziness straight away there – this genius was working out the probability of the behaviour of almost all of the phenomena in our universe by drawing some arrows on a piece of paper? Yep! Told you existence is weird!
Here is a quick summary of the main points he made about the behaviour of our curious universe – the work I’ve just mentioned on the amplification and suppression of probabilities. He also illuminates (yep!) how light reflects from all parts of a mirror and not just those closest to the angle of incidence. He shows how light travels in paths other than a straight line, how photons travel faster or slower than, and not just consistently at, the conventional speed of light, and how electrons go backwards in time. He also explains how photons suddenly disintegrate into positron-electron pairs. For a more thorough explanation of those wonderful ideas, please do read the book – it really is fantastic. And I’m nowhere near smart enough to relay the ideas in any detail.
Now, quantum electrodynamics is important – because it explains ALL the phenomena of the physical world. Well, except, as I’ve previously discussed, the gravitational effect – and also radioactive phenomena (nuclear physics). And Feyman accepted that, while the results of his work were clear, the reasons behind them were less apparent.
“It is not a question of whether a theory is philosophically delightful, or easy to understand, or perfectly reasonable from the point of view of common sense,” he writes. “Theory of quantum electrodynamics describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you can accept Nature as she is – absurd.”
All chemical reactions are explained by quantum mechanics – it is the theory behind chemistry itself – it shows us why oxygen atoms combine with hydrogen to make water. And quantum electrodynamics is just an element of quantum field theory, which explores the electromagnetic field and electrically charged particles – it investigates and illuminates the way light and matter behave.
I don’t know about you, dear reader – but I actually take comfort in the random, contingent nature of existence. The Freudian side of me would suggest there is more to determinism than meets the eye – certainly when it comes to some of the choices we make. But I think I shall at least adopt a Sartrean perspective for now and accept that those little things which made us who we are – our parents being born, meeting each other, falling in love (maybe) and creating you or I – are all just complete coincidences and are not based in fate or some kind of predestined pathway. At least that’s how I see things. Some of you might find all those probabilities and contingencies nauseating, but I just see them as part of our collective path as a species. Where it will lead, who knows? Probably nowhere good – hopefully heaven, or some amazing galaxy light years away where beer doesn’t give you a hangover. Actually, scratch that – if you read this piece of mine on moderation, you’ll already know that I believe all the best things in life have to come at a price to give them worth.
I don’t mind being part of an existence which appears to have no narrative – I don’t mind that there is no grand plan. It means that we are free to make our own decisions and take responsibility for our own choices in that Sartrean existentialist sense – to write our own stories. And just like Nietzsche showed us with his Amor Fati, fate is to be seized and cherished – whatever happens. We need to embrace the utter improbable nature of our being – we need to appreciate this bizarre gift of Being of which we are an inextricable part. Once you have Been you will never be Unbeen. You will one day not Be – but you will always have Been. Make your mark on the world – and try to do by promoting Genuinity; be kind, compassionate, protective, nurturing and supportive. Look after your fellow human beings – connect with them and share your experiences together. This is how you will leave your indelible mark on this wonderful, weird, unlikely, improbable existence of ours.
Electrons and the Taoist universe
If you have read any of my posts prior to this physics/science series, you will be well aware of my appreciation of Taoism by now. I find a great deal of the lessons and wisdom imparted by Lao-Tzu’s Tao Te Ching incredibly enlightening and relevant to what I perceive as the best way to live a contented life. And it seems that science agrees! At least in terms of the way that the workings of the universe mirror so many elements of Taoism (this is, of course, the whole point – The Tao literally translates to the The Way, and is all about attuning oneself to the rhythm of nature/the universe).
In his wonderful book QED: The Strange Theory of Light and Matter, Feynman writes about the crucial role polarisation plays in the behaviour of electrons. It seems at the fundamental level of existence that we need that opposition represented by yin and yang in Taoism; we need difference – we need two sides to tell a whole story (at least, to keep it interesting!) Chemical reactions can’t work without polarisation – without both positive and negative charges, electrons would simply cluster around the nucleus of an atom and no reactions would take place. That would certainly make the world a boring place!
Feynman explains how there are three fundamental laws to the workings of the universe – three basic actions which make the world.
1. A photon goes from place to place
2. An electron goes from place to place
3. An electron emits or absorbs a photon
According to the exclusion principle, electrons (unlike photons) avoid each other like the plague. No two electrons with the same polarisation can be at the same point in spacetime. This is the origin of the great variety of chemical properties of the various atoms which paint the picture of existence. And there also anti-particles – positrons. And in keeping with the weird nature of reality, they are capable of some surprising behaviour. As Feynman reveals: “Every particle in Nature has an amplitude to move backwards in time, and therefore has an anti-particle.” If you read my previous piece on thermodynamics (Part 5), you’ll know that time as we know it is merely a construct of our available mental faculties. But it’s still pretty mind-bending, right? When a particle and an anti-particle collide, they annihilate each other and form other particles (an electron and positron = usually a couple of photons).
I’m not sure I fully understand all this stuff, but it’s pretty cool nonetheless. I find it fascinating that all these imperative reactions are happening at the quantum level to provide the landscape of existence as we know it. All these (seemingly) simple reactions are creating a complex world. There are more than 100 different kinds of atoms which are simply made of protons exchanging photons with electrons, Feynman tells us. Metal, gases, crystals – hard, soft, coloured, transparent. They’re all a result of the exclusion principle and the repetition of the three laws on how electrons and photons behave. As previously mentioned (but worth repeating!) almost all the phenomena – large or small – in the universe is produced by the interaction of electrons and photons and is described by theory of quantum electrodynamics. Fascinating!
I also find it fascinating that opposites attract (and repel!) to create. I think this kind of message can help us to remember that it’s okay to have differences – it’s okay to be in opposition (over certain things, anyway). It’s okay to have your own opinions and beliefs. We don’t all have to sing off the same hymn sheet – or even consider a hymn sheet worthy of singing from (for the record, I don’t believe in god, but I do love belting out a hymn). I have written previously about altering (or opposition) being problematic in the tussle to gain equal rights for women, so I should be careful what I say here. I agree with Simone De Beauvoir that the nature of altering between men and women has set the latter back in their quest for deserved parity. So there are plenty of examples where a little more synergy and cohesion would make the universe function in a better way (or at least humanity’s part in it). But the point I’m trying to make here is that it’s good that we have different viewpoints; different tastes; different styles. It’s in our very nature (the nature of the cosmos) to be poles apart sometimes. Just as long as we try to be kind, compassionate and let our Genuinity flow, we can still try to work towards a world of peace AND difference.
Wu Wei, water and resistance
Anyway, back to the Taoist universe – because there is another revelation in Feynman’s QED book which has strong resonance with The Tao. Feynman speaks about the principle of least action when he describes the way that photons and electrons behave with his probability amplitudes. Light reflects off surfaces like glass and mirrors. And as I previously stated, Feynman revealed that when it does so, it reflects off the whole surface – not just those parts closest to the angle of incidence. However, the reason the probability amplitude is highest for the angle of incidence is because this is the quickest path for the photons to travel – it’s the principle of least action at work. The universe works efficiently – tending to do things in the most practical manner possible. It’s the same with electrons – Feynman explains how classical physics marries up with QED and probability amplitudes to show how electrons move through electric and magnetic fields in a way to make certain that quantity is the least – or in other words, via the quickest paths.
The principle of least action is just another way of describing the Taoist notion of Wu Wei – a profound state of concentration which tells us to go with the flow, be like water and work with (and not against) nature. It is Taoism in action – ‘without doing, causing or making’. To reach Wu Wei one must operate on the principal of minimal effort. “Tao does not do, but nothing is not done,” writes Lao-Tzu in the Tao Te Ching. No egotistical desire. No stress. No struggle. One must be like water – flexible, submissive and weak. And yet unable to be pulled apart – water flows over what is hard and strong. Any obstacle can be worked around and gradually eroded. As Benjamin Hoff relays in the marvellous Tao of Pooh, ‘A mind that thinks too much and tries too hard is likely to fail.’ We could all benefit from attuning ourselves to the workings of nature – to the will of the universe. Don’t rush – stay calm. Remain focused – but don’t let your focus consume you. Be still – be at one with the nothingness.
Chuang-Tzu is one of the great Chinese philosophers, whose most important book goes by his own name and is considered the bedrock of Taoism alongside Lao-Tzu’s Tao Te Ching. He wrote this on the great nothingness (supposedly anyway – it’s all quite conjectural who really existed as it was all so long ago!):
“To have no thought and put forth no effort is the first step towards understanding the Tao. To go nowhere and do nothing is the first step towards finding peace in the Tao. To start from no point and follow no road is the first step towards reaching the Tao.”
Nothing wrong with being wrong
And so we reach the end of this particular blog piece. I’d like to finish by going back to Feynman – although there are certainly Taoist elements in the notion of accepting that it’s okay to be wrong – The Tao informs us that it’s good to understand that we have limitations, and that knowing this can make us stronger. But back to Feynman, because for all the amazing, insightful, helpful and awe-inspiring things that he passed on to the world in his theoretical work, experimental work and various bits of literature, his messages on the art of being wrong probably resonate the most with me. Because this attitude is not just vital to scientific progress – but to life itself. Once we realise that it’s okay to be wrong, that we learn by making mistakes, and that absolutes can be dangerous, we open ourselves up to a world of increasing new possibilities. As Feynman says: “Being wrong isn’t a bad thing like they teach you in school. It is an opportunity to learn something.”
Whatever your opinion on science and its relentless pursuit for answers, ever-increasing depth of inquiry and fierce opposition to modes of thought which aren’t based on experiment or evidence, it undoubtedly teaches us valuable lessons in terms of accepting our limitations, and realising it’s okay to be wrong. In fact, it’s much better for everyone if we’re all willing to accept that we might be always be wrong. Sure, you need to fight your corner, stand up for what you believe in and back yourself when you believe you’re right about something. But we also need to be malleable, open to change and adaptable enough to alter our thoughts if new evidence convinces us to do – we need to recall that Taoist perspective which is so central to my concept of Genuinity (your inner voice/most true nature). The more open we are to new syntheses, the better life can be. As Carlo Rovelli states in Reality Is Not What It Seems: “To accept our ignorance in the first place seems to me to be the truest, the most beautiful and, above all, the most honest way.”
Of course, for people of science like Rovelli and Feynman, accepting one’s ignorance is perhaps the first step towards progress further down the line – but proof remains the goal.
Or as Feynman put it: “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong. In that simple statement is the key to science.”
Truth is, therefore, not an absolute – but rather just based on a kind of ‘scalability’. In Feynman’s words: “The statements of science are not of what is true and what is not true, but statements of what is known with different degrees of certainty.”
Ultimately, we have a responsibility to show future generations that it is okay to be wrong – fear of failure cannot be allowed to fester; just as arrogance must be cast aside. Perspective, balance and openness are traits we have to champion.
“We need to teach how doubt is not to be feared but welcomed,” says Feynman. “It’s okay to say, “I don’t know’ “.
Just as one final note, I wanted to add that after writing this post, I read another of Feynman’s books (which is actually just a collection of recorded interviews made readable) – Surely You’re Joking, Mr. Feynman! Adventures of a Curious Character. The book features a series of hilarious, interesting and illuminating anecdotes which paint a kind of autobiographical picture of Feynman’s life. He comes across as a charming, intelligent, funny and intensely interesting man. But also a bit of a cad/womaniser (even though he’s a massive physics geek!) and a huge prankster. Without wanting to sound like a complete bastard here, I think this is why I like Feynman so much – I see a lot of his character in me. I’m obviously not as smart and successful, but I like to think I share his cheeky side, zest for fun times, drinking and general curiosity. If you don’t read that book, at least take these messages from it – enjoy your life. Take risks. Meet new people. Try new things. Don’t do what’s expected of you all the time – challenge yourself. And do what you love – and keep it fun. Because that’s the best way to get the best out of yourself.