“In a way, the study of killing in combat is very much like the study of sex. Killing is a private, intimate occurrence of tremendous intensity, in which the destructive act becomes psychologically very much like the procreative act.”

Grossman compares the repression and obsession with violence and killing to that of sex in the Victorian era. He seeks to expose the trauma and emotional intensity of killing. Just as it was psychologically unhealthy to repress all public discussion of sex, the denial of the impact of killing on combat soldiers is also harmful.

“The simple fact is that when faced with a living, breathing opponent instead of a target, a significant majority of the soldiers revert to a posturing mode in which they fire over their enemy’s heads.”

Comparing the killing potential of weaponry and actual kills in the American Civil War, Grossman highlights the innate inhibition toward killing a member of one’s own species. He notes that fight or flight are not the only response options and adds posturing and submission. The majority of humans choose posturing over killing.

“The process of some men electing to load and provide support for those who are willing to shoot at the enemy appears to have been the norm rather than the exception.”

After reviewing historical sources and considering the capability of weaponry, Grossman concludes that, at least since the Civil War and through World War II, most soldiers did not want to kill and found other tasks to avoid killing. This innate inhibition, when overcome with The Impact of Training and Conditioning for Violence, will lead to psychological trauma.