What is the biological logic behind the respect of the dead?

Question

I was wondering if we should respect dead bodies. The thing is that I feel I cannot show a disrespectful behavior towards a dead relative or a pet, but I cannot find any logical/rational argument for it.

I mean, I think there is no practical reasons to show respect for the dead, you don't get anything and that person is dead (I'm atheist) so it makes no sense.

So I thought it is only backed by our irrational feelings embedded in our biology. But, maybe there's some biology rationale behind this because it gives us some advantage or benefit... I don't know, so here I am.

Thank you.

Answer 1

Because the dead body looks just like the person, anything you could do to the dead body will somehow communicate to your personal habits that this is OK to do to persons, too. Thus a person who wishes to control his or her self will find at least this virtue in respecting the dead.

Likewise, we perceive that a horse, cat, or dog is like a person, and so we find it objectionable to be cruel to an animal, even when we do not believe that it is immoral to "harm" the animal.

I just thought of a practical reason to add to the aforementioned habit-forming reason: it is not always easy to know when exactly a person is dead, or whether they will just wake up. So as long as the possibility stands, however remotely, that they really aren't dead, it is risk-averse to treat dead bodies as if they were alive.

Answer 2

1. Identity
   Both humans and animals build visual identity for an individual. When the individual dies, they still maintain most of the visual cues that tell the brain "this is so-and-so". I would argue that it's likely that we don't have innate respect for the dead so much as we carry respect from the living person to the dead.
   
2. Uncertainty
   Up until modern times, as Elliot states in his answer, we weren't exactly adept at knowing whether or not people had actually even died or not. This is the origin of the "wake", where ample time is given for the potential dead person to wake from what might just be a coma.
3. Sociocultural
   The fact that sociocultural norms enforce respect for the dead is obvious and doesn't answer the spirit of your question. It may be more useful for me to note potential reasons for why we may have developed these social and cultural norms.
   2.1. Misunderstandings about Death by Early Man
   In Jaynes' origins of human consciousness, he spends some time on the topic of misunderstandings and overestimations of our ancestors interpretation of their own thoughts. He argued that the development of complex language was a tool that enabled complex thought. The pairing of these new tools enabled the audio-hallucination that is replaying in your head something someone once said. Imagine being an early human, listening to the words of your mother or father long after their death.
   Jaynes argues that early respect for the dead and many ancient religions that deified ancestors originated with the misconception that they were not actually dead, just changed or on another plane. He speaks about some of the world's earliest religions, some of which have customs that include changing clothes on skeletons, mummification for preservation, feeding skulls directly, and divination/necromancy that focuses on speaking directly to the recently deceased.
   That would absolutely explain a great deal about the development of such norms despite their total impracticality. The beginning of such customs also coincides neatly with the expected time frames for the development of complex language. Of course this is just a theory and one with its fair share of gaps.
   Jaynes is not the only one to argue for this theory, but he is the last author I read that wrote at length about the subject.
   2.2. A Development of Early Religion
   Early development of religion was very much centered around cycles, likely because this helped form the first practical basis for understanding seasonal change which was arguably pretty important to survival in the harsh climates humans inhabited. We are soft-skinned, fragile, hairless apes after all. I remember reading an archaeology journal quite a while back that I wish I could reference, but it had a paper that went on at length stating that early human burial (not universal) and respect for the dead (not just of humans but of animals, also not universal) came from developments in early religious philosophy that the dead are an important part of the cycle of life and death that allowed humans to live and that they should be respected for their part in this cycle. I don't know if there's any merit to this, but I do remember that the paper showed that North American tribes which put a great deal of stock in these concepts also seemed to put equal stock into burial and respect for the dead. If anyone has any disagreements with this please comment, I'd be happy to learn more as to whether or not this holds weight.
   also, I know for a fact that a number of tribes that had these themes in their religions were also known to greatly disrespect the dead of their enemies, so again, please comment and I will edit accordingly.
   2.3. Practical Concerns
   I know a number of sources that state that prevention of disease and smell as reasons for burials. However, humans have been burying their dead long before the construction of static civilisation centers where this might have become a notable enough problem to merit a burial, so I have concerns that this probably has more gaps than I'm comfortable with.

Answer 3

It's not biological logic as we can plainly see as no other animals actually have rituals surrounding death, like burials or cremations.

It's more anthropological and cultural logic that you need to look at. Also in the philosophical literature, Antigone has been a locus of argument between Natural Law or the Law of the gods as opposed to the worldly and temporal laws of men.