The Errant Experts Who Cry "Impossible!"

The controversial EmDrive device offers a hope of a revolutionary new method of space travel that could greatly shorten trips to the Moon and Mars. It's a propellantless propulsion device. Even after sizable evidence had accumulated that the device did indeed work, various scientists declared that it is “impossible,” that the device could not work. Now (as discussed here) a new peer-reviewed scientific paper has found that the EmDrive device does indeed work, providing a significant thrust. 

An EmDrive device

How could so many physicists have got it wrong? An example was Cal Tech physicist Sean Carroll, who had this to say last year about the EmDrive:

The more recent “news” is not actually about warp drive at all. It’s about propellantless space drives — which are, if anything, even less believable than the warp drives....The “propellantless” stuff, on the other hand, just says “Laws of physics? Screw em.” ….What they’re proposing is very much like saying that you can sit in your car and start it moving by pushing on the steering wheel....There is no reason whatsoever why these claims should be given the slightest bit of credence, even by complete non-experts.

Carroll's blunder is an example of a type of misfire we have seen again and again. Once upon a time, scientists discovered a few assorted facts about nature, a few pieces of the vast cosmic puzzle. Soon thereafter, the heads of our scientists started to swell like balloons. They started depicting themselves as great lords of knowledge, who had learned enough to issue pronouncements such as This is the way that nature always behaves or That type of behavior is forbidden by nature. Such pronouncements are usually just bombast and bluster, and are often no more reliable than the pronouncements of sectarian theologians.

Here is what is typically going on when a scientist says something is impossible:

1. A scientist assumes that some particular unproven assumption (call it assumption X) is true, largely because such an assumption is popular among his colleagues.
2. The scientist then considers some proposed phenomenon (call it phenomenon Y), and judges that such a phenomenon cannot be occurring if assumption X is true.
3. The scientist then declares that phenomenon Y is impossible.

Such a declaration of impossibility is usually dubious, because it relies on unproven assumptions. If such assumptions are wrong, the “impossible” phenomenon may be perfectly possible.

An example of such a declaration of impossibility occurs when a scientist declares telepathy or extrasensory perception (ESP) to be impossible (despite compelling laboratory evidence for its existence). Below is what is going on:

1. The scientist assumes that a particular unproven assumption is true, the assumption that the human mind is purely the result of brain activity, largely because this assumption is popular among scientists.
2. The scientist then considers the possibility of telepathy, and judges this to be impossible if humans minds are purely the result of brains, based on the difficulty of signals passing out of the brain and traveling through the skull.
3. The scientist then declares that telepathy is impossible.

But the reasoning is invalid because the first assumption is not only unproven but actually extremely dubious. We are not entitled to conclude with any confidence that our minds are purely the product of brains, because (as discussed here) we have no understanding of how 50-year old memories could possibly be stored in brains, which are subject to such high structural and molecular turnover that memories should not be able to last for more than a year. Nor do we have any understanding of how brains could possibly achieve the instant recall of obscure memories that our minds display. We are told this involves molecular actions, but complex molecular reactions occur way too slowly to account for obscure memories that are retrieved in half a second (as we see happening on television shows such as Jeopardy). It takes a minute for cellular molecules to transcribe a single protein from the data in DNA, so how many minutes would it take to read some memory stored in brain molecules? Then there's this problem: how on earth could a brain ever know where some particular memory was stored inside it? Don't tell me your brain searches through your neurons, because that would take way too long to account for obscure memories that are retrieved by quiz show contestants in half a second.

It short, claims of the impossibility of telepathy rest on utterly dubious dogmas about the source of the human mind, dogmas that no scientist could be justified in proclaiming until he can give a detailed plausible story of how our brains might be able to store memories for 50 years, and also instantly retrieve them (something our scientists are nowhere close to doing).

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A particularly errant creature is the scientist who assures us that there is “no need” for him to examine evidence in favor of some phenomenon that he has declared to be impossible, on the grounds that it conflicts with some cherished unproven assumption of the scientist. By such strange pretzel logic, such a scientist may try to print himself a permission slip for ignoring the very evidence that he should have evaluated before even making the unproven assumption.

Let's look at some examples of some things that one might be regarded as “scientifically impossible,” but which are actually no such thing. An example is the levitation of a material object or a human body. Science has merely established that there must be a downward gravitational force acting on a body positioned on a planet. But science in no way guarantees that there will not be an upward force (material or immaterial) acting underneath such a body, pushing it up with a force exceeding the downward force of gravity. So levitation is not actually impossible, and could be achieved through various means. Of course, humans are actually levitated in some tornadoes.

Other examples of things sometimes said to be scientifically impossible, but not actually so, include things such as sudden cures, mind-over-matter, apparitions, and life after death. No such things violate any known law of nature that can be specified, so they are not impossible. Arguments attempting to show the impossibility of such things always boil down to: I presume that nature works in this particular way; but if nature does in such a work a way, that thing could not occur; therefore, that thing is impossible. Such reasoning has little weight, because our understanding of how nature works is paltry and fragmentary. Contrary to the overconfident bluster of so many scientists, we have a very good understanding of neither life nor Mind; and we don't even understand most of the material substance in the universe. How can we claim to understand nature well, when something as simple as the vacuum of space is a great thorn in the side of the modern physicist, having a nature completely different from that predicted by theoretical quantum considerations? And if we don't understand something as simple as a vacuum, what pretentious hubris is it for us to act as if we understand such infinitely more complicated things as biological life and Mind?

Postscript: We can put down cosmologist Ethan Siegel as another scientist who just won't accept the EmDrive results (based on what he says here).