Thoughts on reality

Now faith is the substance of things hoped for, the evidence of things not seen... through faith we understand that the worlds were framed by the word of God, so that things which are seen were not made of things which do appear. (The Epistle to the Hebrews, 11:1, 3.)

The objects cognized by the physical senses have not the reality of substance. They are only what mortal belief calls them. (Science and Health with Key to the Scriptures, by Mary Baker Eddy, 311:26-28.)

Schrödinger's famous thought experiment poses the question, when does a quantum system stop existing as a mixture of states and become one or the other? (More technically, when does the actual quantum state stop being a linear combination of states, each of which resembles different classical states, and instead begins to have a unique classical description?) If the cat survives, it remembers only being alive. But explanations of the EPR experiments that are consistent with standard microscopic quantum mechanics require that macroscopic objects, such as cats and notebooks, do not always have unique classical descriptions. The purpose of the thought experiment is to illustrate this apparent paradox. Our intuition says that no observer can be in a mixture of states; yet the cat, it seems from the thought experiment, can be such a mixture. Is the cat required to be an observer, or does its existence in a single well-defined classical state require another external observer? Each alternative seemed absurd to Albert Einstein, who was impressed by the ability of the thought experiment to highlight these issues. In a letter to Schrödinger dated 1950, he wrote:

You are the only contemporary physicist, besides Laue, who sees that one cannot get around the assumption of reality, if only one is honest. Most of them simply do not see what sort of risky game they are playing with reality—-reality as something independent of what is experimentally established. Their interpretation is, however, refuted most elegantly by your system of radioactive atom + amplifier + charge of gunpowder + cat in a box, in which the psi-function of the system contains both the cat alive and blown to bits. Nobody really doubts that the presence or absence of the cat is something independent of the act of observation.[5]

Another thinker writes:

Experimental Psychology has traditionally been partitioned into separate subdisciplines, with surprisingly little communication across the boundaries. Cognition has traditionally occupied one subdiscipline with perception and action occupying another subdiscipline. As a result, theories of cognition have typically neglected the perception and action side of our everyday experience. However, it is possible-even likely-that cognition is constrained by human perceptual-motor capabilities. Furthermore, it is likely that perception and action are constrained by cognition. If such constraints exist, then by ignoring them, cognition researchers have been negligent in their pursuit of a complete picture of human cognition. (The Atomic Components of Thought, abstract of Chapter 6, Action and Perception.)

"As a man thinketh..."