Monday, 17 April 2017

On Quanta and Trees

Does Observation Create Physical Reality?

Image found on Mythapi Facebook page. Author unknown
Posted by Keith Tidman
The intervention of conscious observation into the quantum world — that observing an object to be in a particular location causes it actually to be there — is one of the core tenets of quantum theory. A tenet rigorously upheld through multiple experiments. The observer — his or her consciousness — cannot be separated from that physical reality. There is no reality independent of observation. 
As the visionary quantum physicist John Wheeler stated it, “No . . . property is a property until it is observed.” Which seems to apply as much to macro-sized objects — things in everyday life — as to micro-sized objects.

Three hundred-plus years ago, the philosopher George Berkeley prefigured the spirit of quantum theory’s then-future influence on the nature of reality, declaring, esse est percepi [to be is to be perceived]. Perception, he presciently advocated, is the essential benchmark — the necessary condition — for existence. The reality of things thus emerges from perception. As long as conscious observation is involved — a manifestation of the observer's capacity to consummate physical reality — all objects, large and small, acquire their existence.

So, how does this work? Quantum theory explains that until observation occurs, a potential object was in what’s called a state of ‘superposition’. An object, while in superposition, can be in any number of places, with observation causing it to be in just one location. There was no object isolated in space before it was observed or measured. Upon being observed, the object went from potentiality to actuality in that one location, the same for everyone.

What’s in superposition is the so-called ‘wave function’ — a mathematical description of all the possible states of an object. Only upon being observed does the wave function instantaneously and irreversibly ‘collapse’, causing the object to be in just one location. There is no distinction between the wave function and the object. According to the physics, the wave function is the object — in one-to-one correspondence with the physical thing.

The effect of observation and measurement has also been demonstrated by the so-called ‘double-slit experiment’. A stream of photons (light particles) passes one at a time through a screen with two slits. Behind the screen is a photographic plate, to capture what comes through the slits. In the absence of an observer, each photon will have appeared to pass through both slits simultaneously before creating a distinct interference pattern on the back plate — acting, in other words, like a wave, able to pass through both slits at once. However, in the presence of an observer — a person or detecting device in front of or behind each slit to see which slit the photon goes through — the interference pattern no longer shows up. Each photon appears to have passed through only one slit or the other. The photon has no location in spacetime until it’s observed or measured.

As suggested by both examples — the collapse of a wave function and the double-slit experiment — observation may be performed by a person directly and in real time. Or, observation may be accomplished by an apparatus (detector), whose measurements are observed by scientists later. In either case, observation remains critical, as explained by physicist and philosopher Roger Penrose:
“Almost all the interpretations of quantum mechanics . . . depend to some degree on the presence of consciousness for providing the ‘observer’ that is required [for] the emergence of a classical-like world.”
Meanwhile, the effects of these events also play into what’s known as quantum entanglement — what Albert Einstein famously dubbed ‘spooky action at a distance’. Quantum entanglement occurs when two particles remain ‘connected’, without regard to time and distance — that is, instantaneously, even at enormous distances — in such a way that actions performed on one particle are observed to have an immediate and direct effect on the other. This curious phenomenon, spooky or not, has been confirmed.

So, to the point, what does all this tell us about physical reality?

Causing the reality of an object by observation points to this initial moment of creation being subjective. It’s where an observer first intervenes — until which there is only ‘potential reality’. Accordingly, ‘initial reality,’ as we might call it, requires intervention by an observer — either a person or measuring device. Again, that initial moment of reality is subjective.

However, once initial conscious observation has occurred, the object henceforth exists for everyone. Further instances of observation change nothing about the physical reality already having been created. Reality is thus locked in for everyone — everywhere. Everyone who looks will find the object there, already existing. At that moment, reality is objective — the initially observed object remains so, existing for everyone.

In sum, then, the key takeaway is the presence of both a subjective and objective aspect to reality, depending on the moment — initial observation followed by subsequent observation.

At the moment of causing the object to exist, the observer also causes that object’s entire history to exist. Observation causes both the current reality and related past realities (history) to exist. Whether this is so for literally all observed things remains debatable — quantum mechanically, cosmologically, and philosophically.

Might the notion include, for example, the whole universe — the ultimate macro-sized object? As Wheeler postulates, in our looking rearward to the universe’s beginnings, might our observations result in selecting one out of alternative possible cosmic quantum histories, back to the Big Bang almost fourteen billion years ago? And, in line with the ‘anthropic principle’, might that quantum history account for the many finely tuned features of the universe essential for its and our existence — resulting in an objective macro-reality, the same for everyone, throughout the universe?

Accordingly, Berkeley argued that observation accounts for what gives material things their experienced qualities — an object’s initially experienced reality (its presence and qualities) as well as an object’s subsequently experienced reality.

Where Berkeley’s philosophy converges with the core of this discussion regarding the basis of objects’ reality is his argument for observation — perception — being essential for something to exist. What has been characterised as Berkeley’s empirical idealism. Berkeley argued that material objects are dependent on, not independent of, observation. In this important sense, observation and existence are the same. That is, they ‘cohere’.

2 comments:

  1. George Berkeley was a very interesting philosopher. As I remember, his big interest (being a bishop) was that the world exists because it is seen by God, or something like that. Would you include or exclude Berkeley's notion from your 'observing an object causes it to be there'? and on what basis?

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    1. Actually, I did consider the point you make, Thomas, when I originally drafted the essay — especially the passage toward the end about “cosmic quantum histories [dating] back to the Big Bang almost fourteen billion years ago.” Obvious, I suppose, but I concluded that one could not decisively rule out the possibility of a god acting in the role of ‘observer’, leading to our universe’s bursting onto the scene. But, that scenario was something I considered not only unknown but (agnostically) unknowable. Which is why I couched the discussion of cosmic creation, in the third paragraph from the bottom, in the form of questions. All that said, an observer, like a god, external to the universe would not have been indubitably necessary for the natural wave function of our universe, from among an infinite number of possible universes, to result in its early hot and dense state. Still allowing for what has been acknowledged as the astonishing success of quantum theory (the precision and accuracy of its predictions) — including the role of human observation/measurement integral to the processes my essay describes.

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