Reality Reality

Thats reality in two places at once, in case you were wondering.

The BBC really are excelling themselves lately, first it was Chaos, then last week the excellent “What is one degree” and tonight (on BBC2 and still on Iplayer for a month) for me the best of all,  “What is reality“.

I had never seen anything so intriguing as the experiment of the laser sending single photons through the two slots.  My first thought was that the interference pattern occurs if you remove the concept of time but that is only half the problem.  This was such a simple demonstration of the observer being part of the experiment that I will never ever forget it, and perhaps never ever understand it.

That plus the reasoning behing the holographic universe with the possibility of a two dimensional event horizon holding all the information necessary for our 3D world to be projected. Wow, my head still hurts.

Never has a tagline been so appropriate for a TV show:

be warned: by watching this, you risk never seeing reality in quite the same way again

The only sad part of the show (spoiler alert) was the final idea that we live in a mathematical world and it will be the mathematicians that will solve ‘reality’ first. I dont agree and think that ecologists are almost there. My experiences of lifelong nature reserve managers and dedicated conservationists are that they hold the key to what reality really is. Ive seen that look of contentment as they go silent at every bird call in the distance, Ive recorded the sense of belonging of volunteer wardens in the reed beds of the fens and ultimately observed (hopefully without nullifying the experiment) first hand the use of dowsing rods in the woodlands of Kent to plot the interconnections between age old ants nests.



  1. I agree the two slit experiment was wonderfully shown. I have known of this and others similar (the whole thing gets wierder and wierder) for a few decades now, but as you say, what does it mean?

    I thought towards the end it got flippant though, to say the world is mathematics is an attempt to trick people into thinking it is meaningful because it sounds so esooteric, (sic) and from a scientist too!

    The programme did not cover the many other avenues towards what is reality, which enhance a scientific view more than trying to get further with quantum and holographic multiverses. I would suggest reading and listening to David Deutsch. In his book The Fabric of Reality he has at least 4 types which are of course somehow woven together. There is the quantum reality, and then there is the reality of functioning copy, and then functioning evolution and then functioning intelligence, but you need to read the book to get this. Stewart and Cohen are good with Figments of Reality.

  2. Hi.

    I have mixed feelings on this program “What is Reality”. Overall, I can say that I enjoyed it and found it very interesting. I first learned about the twin slot experiment about twenty years ago and was deeply intrigued by it then. On the other hand, I also found the program lacking in some ways. I shall try to explain why I say this. We were given what seemed to be the “best” understanding on the subject by a collection of experienced, very intelligent scientists, but actually I found their views to be somewhat limited; although their ideas seemed to be presented to the viewer as the best available. Since first coming across the twin slot experiment, I have spent many years puzzling over the problem and tried to find other explanations. I looked at both western and eastern philosophies for some answers. It soon became apparent that eastern philosophers had a much more consistent understanding and explanation of reality. Simply put, reality is dependent on the mind or the observer, or the mind of the observer. Although it seems to be the case that an independent reality actually exist separate from the mind, this appearance is deceptive. The outcome of the twin slot experiment shows this quite clearly. The results are completely dependent upon human observation. There is no independent reality, or independent result. If we look closely, we can see this throughout quantum physics. Is an electron a wave or particle? Of course it is most definitely both, but if we examine very carefully, we can see that it depends entirely upon an observer. There are many mysteries in quantum physics, for example, entangled systems, the measurement problem, all of which stop becoming such mysteries when we let go of our view of a concrete independent reality and think more in terms of an inter-dependent relationship between observer and object. Of course this is quite a profound discussion and wont easily or quickly be resolved. As I said earlier, I enjoyed the program, hopefully it will get people thinking, but I was a bit disappointed. I thought the view of reality put forward was very limited and didn’t look further than the western scientific viewpoint, which to be honest, doesn’t really have any good answers whatsoever.

    Many thanks, Simon

  3. The two slit experiment

    I have a very different view Simon, and if I may I would like to offer it, having thought about the two slit experiment for a long time.

    First, I think the word observer is confusing. If we replace observer, which suggests some kind of intelligence, with interacting object, then we would be saying that when the photon is released any interaction with an interacting body changes the outcome from one condition to the other. This now seems perfectly reasonable, in that the interaction the photon is changed.

    The puzzle is of course that we seem to have interacted with the photon in position A, yet the behaviour which would have ’caused’ interference is occuring at positions A and B, it surely had already been acting as a wave before our interaction in both places. This has to be the conclusion, things are either at A, B or A and B, or most logically, all over, they cannot be both ‘only at A’ and ‘in one or more more places’. Of course the idea of ‘probability’ is brought in to tell us that the object is only probably located until it interacts. Get that? I don’t. Again, I think we use words we can handle which mislead us.

    If we cannot ‘see’ all of the true nature of the photon in our 4 dimensions, in that in those dimensions it has location ‘probabilistically’, we need to call on the photon’s existence in at least one other dimension. So my conclusion is that in at least one other dimension the photon is travelling as a wave, and part of the energy profile of the photon exists within this wave function.

    So if no interactions occur then the photon continues with all its wave function in place and eventually interacts elsewhere, everywhere, as a wave, its interaction will then finalise and drop down energy wise to the observed event. The ‘interaction with itself’ will have occurred through this additional dimension.

    If however, the first photon has interacted it will have had its wave function in the unobservable dimension disturbed, and the energy from that will collapse all in one place, so it will now continue and interact again but now, as a ‘collapsed’ particle.

    Taking this model, bigger objects like atoms will have a more distributed set of waves in other dimensions than our 4, so the chances of them ‘appearing’ elsewhere and acting as a wave are less, but still there. Very small objects like photons will have more of their energy distributed in the other dimensions (as a % of the whole), so they are more likely to be disturbed out of their wave function.

    This idea may help us visualise how a photon has mass but only when it is moving.

    I am not able to check wether this idea of probability being an activity as a wave in other dimensions is either unique to me (I would guess not) nor whether it helps explain all aspects of the two slit types of experiment (there are many). I am happy to find myself misinformed and return to the drawing board. But I doubt I will want to invoke observers ever, only interacting objects.


  4. Hi Graham,

    I offer my congratulations on a very well thought out explanation of a mind-numbing problem. I will now need to spend some time thinking about your ideas, so I shall get back to you soon, after having thought about it more deeply. Briefly though, I am interested in your reluctance to invoke observers. Do you not think that conciousness forms part of the equation. It’s a very interesting debate, one that I’ve had many, many times with lots of people from various backgrounds, some scientific, some philosophical. Interestingly, I’ve never seen much shift in opinion on either side. For me, a lot seems to come down to the word – “reality”, what does it actually mean. Different people will say different things. Which is correct? I think it’s fair to say that everybody’s own reality is there own and different to that of others. Is there and independent objective reality? This seems to me to be the “real” question or at least the most important question and actually by far the most interesting question. What would be the characteristics of an independently existing object? Very fascinating.


  5. Thanks Simon, I look forward to your further thoughts. As I noted earlier, I think Deutsch offers an intersting development of ideas on what is reality. If one sees it as possible that reality is a multi headed hydra then reality can in part be absolute and in part be relative and personal. There is an emergent reality in our own heads, but the physical reality is also there.

    Consciousness is part of one or more levels of reality, that is Deutsch’s reality of intelligence, which emerges from the reality of evolution. But as the photon level the observer is not conscious, the ‘observer’ is just any interacting object.

    My 3 p worth


  6. Graham, Simon, thanks ever so much for sharing your latest emergent thinking on the subject. I am honoured to have been host to such and I can’t help wondering if a similar discussion is going on in other blogs at which you both come to a completely different conclusion.

    Cheers, Ron

  7. Interestingly the experiments work with beaming individual electrons. This is more important than photons because photons have zero mass and therefore on special relativity, create interesting explanations for certain behaviour in the split experiments. But electrons have mass and travel slower than c.

    It is an interesting thesis that nature reserver managers and conservationists hold a key to the meaning of reality. I expect it would depend on what you mean by reality and I have empathy with certain concepts that consider any form of meaning being relevant within the confines of an anthropological setting. What is the meaning of meaning prior to any beings being able to raise the question of meaning – hence an answer to this question can be usefully raised within that context. But this doesn’t invalidate another conception of reality that recognises that something existed long before any meaningful or useful concept of ecology (at least in any deep sense) could be raised – e.g. at the time of the big bang. But then reality will always outstrip mathematics, which I still consider a communication, calculation and reasoning tool, not a fundamental part of reality itself.

  8. I think it is interesting that people can be single minded about reality! No-one here of course! Mary Midgley is very wise in her book Utopias, Dolphins and Computers. “Minds, in fact, do not seem to be the kind of thing for which the idea of a complete explanation makes sense.”

    She is wise from many different directions, she sees no value in trying to force everything into one form of philosophy or science or faith. So yes, there is a reality in the emergent truth of Macbeth and a reality which recognises that his visions are visions and not reality!

  9. I have to say an amazing honest discussion. Very interesting and great to tap into all this wealth of knowledge. Personally as a person with no background in this area the documentary left me in thought for hours, ‘blew my mind’! Like Simon I felt eastern ideas where missing though. What really kept going through my mind is the uncanny similarities between the question ‘what is reality’ and the question ‘what is enlightenment’. Looking at both philosophies.

  10. Sorry Graham it’s ‘no worries’ I’m afraid. Just a normal sod with a long standing interest in the human condition. Linked here from the horizon website. Was really taken in by this discussion. Fairplay Ron, looking at your three main interests you have achieved all three here!

  11. Two queries and I wonder if anyone can help out.

    For a long time I have puzzled over another couple of odd things and wondered how to represent reality in my mind. In some ways the two slit experiment may be easier!

    The first is the easier one, or there may be an easy answer, I just don’t get it. Why can waves travel thousands of miles across oceans and not lose much energy, and they lose it all as they hit the shore?

    Now I know water is a funny substance, that it is not H2O, it behaves oddly in that it expands below 5 C and it is pretty incompressible (if you fall out of an aeroplane from a great height aim for mud not water!). I guess some of this is because have 27 or more different constantly changing constituents somehow it is superelastic, but for a substance which is a liquid and so atoms and molecules and ions move between each other, for there to be no friction worth talking about seems very odd.

    All explanations most welcome.

    I will post the second more difficult query in a second post.

  12. My second query relates to the law of conservation of energy, which is one law which I really think is a law, no breaking it, ever. I need to work backwards to explain my dilemma.

    Two ‘particles’ come towards each other at a relative velocity v, they have mass m, they have a vibrational and spin energy E, they glance off each other and head in different directions.

    We can calculate how the vibrational and spin energy of each particle have changed from before to after. And we can say that the energy in the relative speed (mass times velocity, taking each of our 3 dimensions into consideration) will equate exactly with the change in vibrational energy change plus any radiated energy from the collision. But if energy as mv is conserved, how does it exist in the relative speed (we know velocity is relative, thanks to Einstein dear lad) and is not located in either of the particles themselves. As energy has mass, where is the mass of the relative velocity?

    I hope you can help me with this. One very clever professor I know said it is a big puzzle!

  13. Can the double-slit experiment be explained by the latest theories on diffraction?

    My question concerns a new explanation of the double-slit experiment that has been posted on the Facebook ‘Quantum Physics Discussions’ page (the title of the posting = ‘Idiots propose an alternative explanation of the double-slit experiment’).

    The new suggestion is that the effects of diffraction can occur when a particle approaches a slit (previously diffraction was only thought to occur as a particle leaves the slit), and that if the two slits are close enough together so that the diffraction effects overlap, then it is this overlap that leads to interference patterns rather than just diffraction patterns. This would also explain why firing one particle at a time produces an interference pattern. Does this explanation have any merit?

  14. What a cool programme to tackle! Although I thought it wrong for Horizon to imply that Lenny (the theoretical physicist) came up with Holographic Principle – as we all know the main initiators into the subject were Karl Pribham and David Bohm! Lenny did actually refer to the subject as a crazy notion from the past that was eventually molded into a tangible subject!! … The programme makers probably edited vast amounts out in the attempt to make this complex subject more understandable to us the dimwitted viewers!!

    I think if you are trying to understand a subject which involves photons being in 2 places at once, then it is probably best to stop thinking of the solution in our ‘linear’ fashion! There is no point A then point B because they are both the same point!

    Also, as someone else posted, it is not just up to scientists to discover principles of reality, but everyday people! I knew a guy who was an absolute loon, but he could tell me stuff before it happened! What is Reality??? Think again!

  15. Coolest programme ever!
    It made me wonder a lot. As an ordinary non-scientific sack of molecules, I started to think a lot about my existence.
    How can one see the holograph in a holographic world? How is that dimensional system working? Is it just like the reflection of the mirror in a mirror?

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