A real problem is that cryptozoology
- is a search for conclusive evidence and
- is defined by the absence of conclusive evidence.
In physics, chemistry, geology, astronomy, or standard biology, the more evidence one has from observation and experiment, the better the science is. By contrast, if conclusive evidence were ever found for the existence of Bigfoot, for example, he would cease to be a cryptid and become just another primate to be studied by professional primatologists -- not by cryptozoologists.
That may seem to be nit-picking, but the reality is that the "scientific method" is cyclic, which allows both theories and experimental methods to be refined. Perhaps some cryptozoological ideas may be falsified by the absence of evidence, but few could be validated. So, for example, some Bigfoot researchers believe him to be descended from Gigantopithecus, some from a common ancestor with humans not long after the divergence from chimpanzees, some that he is something else. With no unambiguous evidence that Bigfoot exists in the first place, there certainly is not enough evidence to constrain such speculation. Likewise, a wide variety of techniques, including the use of recorded sounds allegedly made by Bigfoot, wood knocking, scents and pheromones, etc., are used to try to attract Bigfoot so that photos, footprints, hair samples, etc. might be collected -- so far with (obviously) no unambiguously positive result. Is this because the methods are flawed, or because Bigfoot is rare (or does not exist)?
Remember, one of the "defining characteristics" of pseudoscience is "vague mechanisms to acquire understanding." The fact that cryptozoology, so long as it remains cryptozoology, does not have enough evidence to refine its methodology means that it is always flirts with pseudoscience.
This is the point at which Bigfoot believers jump up and shout, "But what about all those witnesses? What about the DNA and hair samples? What about the footprints?" Some of those are suggestive, and they are the reason I think there is a 1% chance Bigfoot is real (as opposed to the Loch Ness Monster or visiting space aliens, both of which seem much, much less likely). They constitute enough evidence to form a hypothesis, but not enough to confirm that hypothesis, at least in the opinion of the majority of biologists with some relevant expertise. Not being a biologist myself, let alone a primatologist or expert in North American ecology, I'll defer to them.
At this point, another problem with cryptozoology emerges, because by saying I will defer to the consensus of professional biologists, all manner of conspiracy accusations will be brought forward. To be fair, I think it is the mostly the "armchair quarterback" cryptozoology fan who is most likely to believe that there are conspiracies to hide the existence of Bigfoot and other cryptids, followed by the untrained amateurs, but since these two groups make up the bulk of the cryptozoology universe, their schizophrenic love/hate attitude towards established science taints the community as a whole.
The real problem with that kind of attitude is not that it is offensive, but rather that it gives cryptozoology a shove in the direction of pseudoscience. Again, two of the "defining characteristics" of pseudoscience are
- Lack of Organized Skepticism and
- Disregard for Established Results.
The hyper-sensitivity of the cryptozoological community essentially eliminates the possibility of organized skepticism. Members of that community distrust the biologists who actually have a process for organized skepticism -- and they also distrust each other. That's not to say that they make no use of established biology or other cryptzoologists, only that such use shows symptoms of being heavily filtered through their ideas.
Finally, let me return to the "cherry picking" of data I mentioned before. I have seen it argued that the consistency of the sightings of Bigfoot argues strongly for its existence. Well ... not so much.
For one thing, the idea of something intermediate between man and the animals seems to be deeply ingrained in the human psyche. Thus we hear legends of vaguely Bigfoot-like creatures from all over the world, just as we hear legends of dwarfs and giants from all over the world. These ideas are simply too obvious for storytellers not to continually reinvent them -- and they're probably always somewhere in the deep recesses of our minds, too.
Also, of the half-man, half-animal sightings reported in the US, there are very noticeable variations. There are reports of Bigfoot speaking and wearing clothes or a hat. There is the Michigan Dogman and the Skunk Ape and the Lizard Man. If, from such a range of reported sightings, you select the ones that seem most like the creature shown in the Patterson-Gimlin film, you can't use the "remarkable consistency" of those sightings to prove anything.
Lastly, since the 1970's the media have been saturated with representations of Bigfoot and Bigfoot knockoffs (Chewbacca). These provide a stereotype around which to understand any unknown. Something similar seems to have happened with space aliens, which in the US are now typically small "gray" aliens -- though that was not the case 50 years ago, nor is it the case in other parts of the world.
So, after all that, do I now consider cryptozoology to all be pseudoscience? No. I think that trying to construct a "field" of cryptozoology is fundamentally flawed, and there are serious problems with the cryptozoological community. There is a good deal of pseudoscience done under the name of cryptozoology. That does not mean that everything done under the name of cryptozoology, though. Probably the best of cryptozoology should be compared with good amateur astronomy -- though not, so far at least, with as much success as amateur astronomers have had.