One of the points he raises, however, which is a reflection of what Dr. Jacques Vallee has been saying for decades now, is problematic. Mac comments:
As noted by acclaimed researcher Jacques Vallee, the Extraterrestrial Hypothesis (ETH) typically embraced by ufologists fails to account for the phenomenon's enduring weirdness.I have to admit, while I remain a healthy agnostic on the question of extraterrestrial visitation to Earth, I have never understood this particular reason for rejecting the ETH as the most logical of the non-prosaic explanations.
Yes, many UFO sightings are weird in terms of our understanding of what is happening. One of my favourite of the "high strangeness" types of cases happened here in Halifax (see: High Strangeness in Halifax). But that weirdness is not a reason for rejecting the ETH, unless one is viewing possible alien life and through the prism of human understanding. By doing so, both Tonnies and Vallee evince a very 1950s / 1960s sci-fi outlook of what alien life would be like. In short when they state that the weird behaviour of some UFO cases seems to rule out ET as the cause, they are assuming that aliens will more or less act like us, or at least in ways that we can understand. Since the UFOs are not acting in a way that makes sense to us, as aliens presumably would, then they must be something else - extradimensionals, or cryptoterrestrials.
The problem is that this assumption flies in the face of our own human experience when different cultures meet each other. For example, when the first European explorers reached the south Pacific islands, neither they nor the natives even remotely understood each other. History is replete with similar examples.
This happened on a frequent basis when it was different cultures coming in contact with each other, where one was more technologically advanced than the other, but not by a significant degree - decades, or perhaps centuries, but in either case, a drop in the bucket where development is concerned. Even after prolonged exposure to other cultures, profound differences of understanding and perception would remain, which in part would explain the not infrequent colonial disasters that would befall European military expeditions when led by men who had no understanding of the local terrain, or how the natives waged their own style of warfare.
And that's just a difference in understanding and perception between cultures within the same species, all of whom are singing from the same proverbial hymn book, if not the same page. What about differences between different species of vastly different levels of intelligence? How do cats perceive humans, for example, or how do ants perceive humans? Can they understand our behaviour; can we understand theirs?
The point is that just because UFOs might behave in ways that we cannot understand is no reason for concluding that they are too weird to be extraterestrials on the grounds that an extraterrestrial would never behave in such a weird manner. The truth is that we have no idea how an extraterrestrial would behave, or what their motives would be for coming here. This works both ways - they might not be able to understand us, in the same way as we don't fully understand what's going in with various animals when they do certain things. In fact, I would argue that any alien life is likely to be so different from us that we should expect that it will behave in a manner that is completely... well, alien to us.
Does this mean that UFOs might not be extradimensional beings, or cryptoterrestrials? Of course not. But when one tries to determine which of these explanations seems more likely, one should always be careful of basing their conclusions, whether in whole or in part, on the anthropomorphic assumption that because UFOs sometimes behave in ways that seem "weird" to us, it is less likely that they are extraterrestrial beings that cryptos or extradimensional beings.