Except for isolated band-level societies, any given human being on Earth has humans as their top threat to survival. Something another human does will probably be the cause of most of your life-threatening situations. Directly and indirectly, humans are causal for most human deaths. Despite cannibalistic species or those where the young eat each other humans are quite self-endangering. However, this may not be as bad as it sounds.
Don’t take a “reflexively endangered species” hypothesis as a grim outlook for us. Self-endangerment is an inevitable reality for a species that is highly social and highly cognitive. With our great power comes great deficit in responsibility for our own safety. Regardless, I believe some positive insights can be made from this observation of humanity at large. Humans are the main reason why humans die as a consequence of how successful and interconnected they are. As the human-human death ratio increases perhaps it’s just an indicator of complexity of technology and social institutions. A decrease would indicate a simplifying and reservation of human sociocultural evolution. Neither is inherently better, just different in expected life quality and longevity.
For ancient, historic, and even present, Homo sapiens’ and the like killed their own kind unintentionally if at all. Most people want good for others, but most lack enough foresight, analysis, and planning to prevent harm in progress. Especially in times when experience — one of our greatest faculties — does not apply to our development and we are manifesting destiny blind but unbound. In our social labyrinths of today, the vast majority of human-human deaths are side-effects of modern civilization either not keeping up with itself or going beyond it’s current capabilities. Whether this human harm is based on ignorance, misunderstanding, arrogance, or zeal it is address and adapted to; such as the steadily escalating development of bio-medicine. The dangerous, yet potentially life-prolonging, maze of social evolution is an unsurprising result of so many things being done in so many ways for so many reasons by so many people with so many inadvertent dead-ends and spiked pitfalls.
This leads me to see that the increasing human-human kill rate is not an increase in maliciousness, it’s an unintended consequence that pervades humanity because it’s the most likely way things can be. Perhaps our primacy to potentially die by human is not a bane born in blood, hate, and evil. Even in the most hideous deeds, war-deaths, which appear as nothing more than hopeless slaughter and hate between humans are better viewed as a result of instincts and lack of knowledge. Murder in war is a unfortunate inability to think deeply for a way to live in harmony with differing belief systems, to realize that humanity is more precious than (excess) resources; and likewise, to use your energy and wit to produce a world where competition is fruitless. It’s hard to realize those things, to see through the fog of war, even for an intelligent human being. This means “Man’s injustice to Man”, despite being blatantly direct violence, can be seen as indirect by reasons of mind clouding circumstances where a human is made to kill a human and see it as progress, or a necessity to live. It is more an accidental slaying rather than murder and intended injustice to a fellow human. This applies to a human killing someone they see as sub-human; it’s clearly a direct human-human death at first glance but could be indirect as the human didn’t mean to kill a human because to them it is killing a sub/non-human and a threat to humans like you. It’s a disturbing type of human-human death and a grotesque understanding, but I evoke it to demonstrate the degree to which “direct and evil crimes of humanity” is an interpretation just as valid as “indirect and oblivious blunders of humanity”. Let’s look for brighter sides.
So to start turning up a positive route away from the macabre instances of our species let’s analyze human caused deaths of humans for why they are a good sign of human nature. A human can kill a human indirectly through multiple systems but in order to do so this must be in a circumstance where humans are living long and well-developed lives (or given an opportunity or one in partial; or at least life’s interesting with all these systems and hazards). Even cancer and many chronic diseases are an indirect result of another human but only because that human was part of a social structure that facilitates a progressive society that provides enough life span end or harm it in a way not seen when death was by poison mushroom or cold exposure far before cancer or heart disease age. A complex society — and a global supersociety — is expected to produce toxins harmful to itself, it’s a natural biological phenomenon that too much of anything will have negative byproducts. For modern humans we keep growing past that.
Just as noteworthy as anything and the only pure fact I have, is there is disproportionately so many humans to their habitat compared to other species that human-human endangerment is physically necessary. it is a biological universal that high population densities to the edge of carrying capacity will have high deaths from resource stress and inter-species competition. For humans we have at any given moment this mathematical outcome. The thing is we die because rather than starve or fight we make unnatural sub-habitats and survive the normal biological expectations die unnatural and outside biological convention. We are so successful our own survival strategies can kill us other more than all nature’s hazards, and we still grow at exponential rates. What a remarkable and impressive species despite the bleak stats and ratios.
So we are in a time where humans kill humans more than other things kill them, but when that human dies they have lived far more than they would have if they lived in a time that this ratio was not so. Dying from malaria or large cat means you likely were in a life zone in which you would die by 30. Dying from indirect poisoning from a human, a direct murder by a human, or from a human caused accident means you are in a life zone conducive to a life of 70. Neither is objectively better, just an indication of the nature of the humanity. Personally, I’d rather live as a band member and die at 30 than the latter, but that is irrelevant to this concept. It’s another topic to analyze how well of a life is lived in a modern society versus an ancient band or tribe level, but in all truth life is going to be basically the same however. It will involve pain and suffering, joy and wonder, friends and family, and a human experience, one after another. So as terrible as it sounds at first, that humans’ greatest threat is humans is actually a sign of success in our species. When we see that in the past we died three times as young just to live in present where we kill ourselves in elder, we know our species is a survivor and the next era’s leading cause of death will only be an indicator of something really awesome about our species.