Quantum Biology and the Puzzle of Coherence

[tama]

37. Delayed choice experiment

is Wheeler's modification of the original Young's double slit experiment:
http://en.wikipedia.org/wiki/Wheeler%27s_delayed_choice_experiment

If you are looking for empirical evidence of observer effect and "backwards causation", there you go:

John Archibald Wheeler is one of those thinkers who takes the ideas of quantum mechanics seriously. After studying the Copenhagen explanation of the double slit experiment – with its emphasis on what the observer knows and when it is known – Wheeler realized that the observer's choice might control those variables in a test.

"If what you say is true," he said (in effect), "then I may choose to know a property after the event should already have taken place." [1] Wheeler realized that in such a situation, the observer's choice would determine the outcome of the experiment – regardless of whether the outcome should logically have been determined long ago.

"Nonsense," said the reductionists. "Rubbish," said the materialists. "Completely absurd," said the naïve realists. "Yup," said the mathematicians.

And so Wheeler's thought experiment and the predictions of quantum mechanics were brought to the laboratory for testing. [2] This is what happens.

(...)

So it seems that time has nothing to do with effects of quantum mechanics. And, indeed, the original thought experiment was not based on any analysis of how particles evolve and behave over time – it was based on the mathematics. This is what the mathematics predicted for a result, and this is exactly the result obtained in the laboratory.

http://www.bottomlayer.com/bottom/basic_delayed_choice.htm