A Roach's Nervous System

The human nervous system, with its brain and spinal cord forming the central part and the rest of the nerves integrated with the general body, is not only far from the only logically possible nervous system, but it is far from the only kind of nervous system reported to be present a plethora of other animals.  Not even every animal is supposed to have a nervous system of any kind (sea sponges are supposedly the only category of creature this applies to)!  Many of the most neurologically "alien" life forms reside in the world's oceans, while some with drastically differing neural networks inhabit the surface along with humans.  Roaches, despised by many, are among the latter.  Somewhat renowned for their ability to live without their heads, the roach's nervous system is such that what should quickly end the bodily life of a human only starts a limited but extended life without its brain.

This is not an example of a creature with no nervous system or nothing at all analogous to a brain, but it is an example of an animal that certainly appears by all outward evidences to have its own consciousness and yet does not possess a nervous system like that of humans.  Oh, it is supposed to have neurons, and 1,000,000 of them at that, but these are not massed together anywhere in one central brain.  The more conventional brain is in the head and a lesser bundle of nerves is in the abdomen.  A roach would thus have two structures at opposite ends, hence why it can survive for so long without its head, which contains the primary brain of sorts.  The nerve cluster in the abdomen would be relied on.  Spiracles, small holes in its body, allow it to breathe in the absence of a head, though it cannot drink without its mouth and can succumb to dehydration within around a week.

For this period of a week or (according to some) more, a roach can still breathe, move, and otherwise engage in many of the activities it otherwise could with its full nervous system intact.  If it were not for the need to eat and drink, the second of these being the most pressing, the roach could hypothetically live for far longer than this.  Yes, this post-decapitation survival pertains to differences beyond the strictly neurological, such as the way respiration occurs in roaches and other insects, yet even after losing the head, a roach is biologically alive and, as with before, seemingly conscious in a genuine sense, not like a wind-up doll or lifeless AI program.  Its consciousness before and after decapitation is uncertain for me and any other human observer like me, as we cannot even know if other human minds exist.  As as both probabilistic epistemology (which far transcends petty science) and basic, passive scientific perceptions evidence, roaches are likely conscious in both states.

Unlike the sea sponge, which has no neurons, and unlike cnidarians such as jellyfish and coral polyps, which have neurons but no brain, the roach had neurons and something of a centralized nervous system, but it still differs from the human neural structure.  Whereas sea sponges react to stimuli in the most basic of observed ways, anyone who has seen a roach in their living space has the opportunity to realize that it truly seems to be conscious.  Here is a creature that actively scurries about.  Not that it is logically necessary for there to be a body in order for there to be a mind or for every body to have a mind, but, as is the case with the many other animal types I have touched upon before, if outward scientific neurology is as it appears and if roaches do have their own consciousness which behavior hints at, then there is absolutely nothing about the combination of a formal brain and billions of neurons that is logically or (in a lesser sense) scientifically required to have a mind even as a biological organism in this world.