HOUSE_OVERSIGHT_016012.jpg

322
Are the Androids Dreaming Yet?

will have an effect on this decision – constructively or destructively. The photon can’t make up its mind at the first surface. It has not yet seen the second surface.
The photon travels on and reaches the second surface. It needs to make a decision: Shall I reflect or not? It cannot decide that it should have been reflected from the first surface because it is already at the second surface; it’s too late.
The photon is stuck. It cannot make the decision at the first surface because that is too early, nor at the second surface because that is too late. The glass surfaces cannot be the source of the decision.
This leaves only one remaining option: I, the observer, tell the photon what to do. The word ‘tell’ is probably a little strong. Sadly, I am not that powerful. All I can do is tell the photon to make up its mind. When the photon reaches my eye, it must decide what happened to it along the journey, but this decision appears purely random and I have no effect upon it. The best way physicists have found to describe what is going on is to say particles, such as a photons, behave according to a wave function. Particles oscillate between all the possible options available to them and when we take a measurement this freezes the oscillations and gives a single result.
Where exactly is the measurement made? At my eye when the photon is refracted by the lens, when the photon enters the aqueous humor, or perhaps as it interacts with the rods and cones in the retina. Maybe we must wait until the detection of the photon is converted into an electrical impulse in the optic nerve or even the point at which my human consciousness perceives it.
This prompted the physicist John Bell to ask a slightly tongue-in-cheek question, “Was the world wave function waiting to jump for thousands of millions of years until single-celled creatures appeared? Or, did it have to wait a little longer for some more highly qualified measurer – with a Ph.D.?” You see his point. Where is the bar set that defines a measurement?
One of the most extreme answers to Bell’s question is the strong anthropic principle. It argues humans – or at least sentient beings, perhaps even cats – cause the Universe to exist. The Universe bubbles along in a state of superposition with every possible event occurring and bifurcating until an observer emerges in one of the branches and the whole edifice collapses to that state. It is not clear if this produces many concurrent universes or if the first universe with a sentient being wins!

HOUSE_OVERSIGHT_016012