ESP is not produced by the brain.
There is ample proof that ESP is real. However it is not possible for ESP to be caused by the brain because none of the laws of physics, including quantum entanglement, can explain how the brain might produce ESP. And in the case of telepathy, the unique structures in one brain will be meaningless to another brain. The existence of ESP is consistent with and mutually reinforcing to many other lines of reasoning that lead to the conclusions that consciousness is not produced by the brain and that consciousness can exist separate from the body.
No physical mechanism in the brain has been demonstrated to cause ESP. ESP has been shown not to be limited by time and distance. ESP can reach into the past and future and is just as strong over short distances as it is for long distances. None of the known laws of physics can explain this. It has been hypothesized that quantum entanglement could explain ESP, because when two particles are entangled, determining a property of one particle will also determine a property of the other instantly, independent of distance between the two particles. However, quantum entanglement can not be the mechanism by which ESP occurs because for entanglement to occur, there has to be some mechanism by which entanglement is established. In lab experiments on entanglement, the entangled particles are created deliberately at the same time in the same location and then separated to demonstrate entanglement effects. While entanglement can occur in biological systems, as is seen in photosynthesis, in a biological system like photosynthesis, a mechanism for establishing entanglement is easy to explain because it occurs in a very small region at a specific time. However in the case of ESP, there is no mechanism by which entanglement between objects at separate locations could be established to produce forms of ESP such as telepathy and clairvoyance. Microtubules in brain cells have been proposed, by Stuart Hammeroff, as a mechanism for producing consciousness. It has also been proposed that quantum entanglement in that system could explain ESP, but again there is no way entanglement could be established between separate individuals.
Furthermore, even if there were some way to entangle a physical structure in one brain with, for example in the case of telepathy, a structure in another brain, there would be no correspondence between the meaning of those two structures to the consciousness of the individuals. The patterns in one person's brain will not make sense to any another person's brain. The pattens of neurons in the brain develop differently in each person according to their genetics and environment, and those patterns change over time due to neuroplasticity. The meaning of a physical structure or pattern in the brain of one person will be unintelligible to another person. Entangling two structures in different brains would not be able to convey any meaning to either person. Therefore, telepathy cannot be produced by the brain by means of quantum entanglement or any other physical means. The very existence of telepathy, therefore, is evidence that ESP is not produced by the brain, and also that consciousness is not produced by the brain i.e. that conscious is non-physical.
There are also several other independent lines of reasoning that lead to the conclusion that consciousness is non-physical and not-produced by the brain. One of these lines of reasoning, for example, is based on the fact that that consciousness is a subjective phenomena that cannot be measured objectively and therefore cannot be produced by physical processes since all physical processes are, in principle, measurable. The only way to know what is in the mind of another person is through ESP, such as telepathy, or telempathy, both of which are themselves subjective and unmeasurable by any objective physical means. Since consciousness is subjective and non-physical and cannot be measured by any physical process, ESP which can perceive aspects of another consciousness, must also be non-physical, and cannot be the result of any physical process in the brain.
People who believe that ESP is produced by the brain believe that some quantum effect must cause ESP because ESP is independent of time and distance. But there is a much better explanation for ESP that also explains why ESP is independent of time and distance. That explanation is the filter model of the brain. According to the filter model, consciousness is not physical and the brain does not produce consciousness but only filters it. The filter model explains all the facts that are explained by the production model such as the correlation between mental states and brain states, and the loss of functions due to brain injury. But the filter model also explains ESP and why it is not dependent on time and distance. According to the filter model, ESP is the means by which non-physical consciousness naturally interacts with its environment and because consciousness is non-physical it is not subject to the laws of physics or limited by physical parameters such as time and distance. The filter model also explains acquired savant syndrome where brain injury causes new talents to be uncovered and why brain injury sometimes result in development of ESP. These two effects are caused by brain injury that is like a hole in the filter that allows new aspects of consciousness to pass through it. The filter model explains loss of function injuries, such as amnesia, as being like a clog in the filter. The filter model also explains the unfiltered consciousness experienced by NDErs that includes veridical perceptions, 360 degree vision and colors not seen while in the body.
Philosopher Chris Carter believes consciousness is not produced by the brain and that the brain transmits consciousness. Parapsychologists who do not believe in survival have to explain afterlife phenomena as the result of ESP produced in the brain of a living person. Chris Carter's work demonstrates that those theories are pseudo-science.