The much-discussed problem of Schrodinger's Cat Wikipedia has a simple explanation in terms of the theory here. The explanation lies in why the walls of Schrodinger's chamber need to be made of steel i.e., opaque. Opacity does seem to be an unreasonable requirement. If we are worried about extraneous influences affecting the experiment, why not just consider an idealised situation where extraneous influences are ignored? Why do we need to exclude them deliberately? In other experiments we ignore friction when it suits us, or we assume that a test particle is 'small', and so on. In the case of Schrodinger's Cat, it seems essential for the walls of the chamber to be opaque. The implication is that we will not obtain a proper experiment by peering through translucent walls, whether or not we make the idealisation that our observation does not affect the measurement.
According to the theory I am presenting here (something is real if and only if it contributes to the logic of the world), the opacity of the walls is indeed essential to the experiment. We make the chamber opaque so that the enclosed objects (notably the cat) are excluded from our world i.e., they no longer take part in the logic of our world. The paradox of Schrodinger's Cat arises when, having sent these objects out of our world, we pretend that we didn't do that. We pretend the objects are still in our world and that we can look at things from the cat's point of view i.e., from whether it knows it is dead or alive. That is illogical. If we have sent the cat out of our world, it is not valid to pretend that it still remains one of our real objects. The 'paradox' of Schrodinger's Cat comes down to our inconsistent logic (which is what all paradoxes are).
It is interesting to make the walls transparent and see what happens. What happens is that the cat is seen to suffer, the experimenters get chastised, funding dries up - and the threat of that happening prevents the experiment from being done in the first place. So no paradox. One of the experimenters then suggests doing the experiment without the cat - in fact, with nothing in the chamber apart from the triggering atom. The paradox would then involve the radioactive atom being in a superposed state of integrated/disintegrated. Not a big deal. This confirms that the difficulty does indeed lie in taken-for-granted factors such as wall opacity.
The lesson from Schrodinger's Cat is that we need to be careful about what objects are deemed to be taking part in the logic of our world and what objects are not.
I believe Roger Penrose falls into this trap when, in one of his popular books (The Road to Reality, p820), he discusses the asymmetry of time. He describes a simple experiment where a photon is fired at a half-silvered mirror, the electron going on to trigger a detector if transmitted through the mirror or getting diverted into the ceiling if reflected. He invites us to consider the time-reverse of this, starting with the detection of the photon. Given that the photon is detected, where did it come from? According to the quantum formalism, the probability is only 50% that it was transmitted through the mirror. The other 50% probability is that the photon rose from the floor and entered the detector by reflection! This is 'paradoxical' because we know full well that the photon could only have come from the laboratory's photon source. We are 100% certain it was transmitted through the mirror and did not come from the floor.
The mistake is not having the same objects in the world in the two cases. In the forward-in-time scenario, a photon that gets reflected leaves the world by striking the ceiling or otherwise escaping from the system. In the reversed-time version, the photon which Penrose said came from the floor should have been seen as entering the world, because this is the reverse of a photon leaving the world. If we allow for a photon entering the world, it is indeed possible that it ended up striking the detector. The odds on that happening depend on the temperature of the photon when it entered the world. To avoid prejudice, we need to give the photon the only temperature that the system knows about - the temperature of the forward-in-time photon source. When we do that, hey presto, the time-reversed scenario has exactly the same probabilities as the time-forward scenario. The lesson is that we need to be careful about what objects are in our experiment-world and what are not (i.e., about what is being measured and what does the measuring.) In the same way that we choose objects to constitute our experimental system, we choose (but unconsciously) what objects are to constitute the reality of our world.
The next page provides an explanation of how biological complexity comes about. Next page - Page 5
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