Involuntary Quivers*

The essence of sadism is the perverse enjoyment of involuntary reactions, physical or psychological, induced in the victim. Whether this is just a description of an emergent phenomenon or the actual mirror neuron-based foundation of the ability to enjoy inflicting cruelty, I do not know. What I do know is that this is effectively the basest form of empathy: to determine whether or not you get rewarded with sadistic pleasure, your mind needs to be able to model whether or not an involuntary reaction is occurring within your victim. The higher form of empathy - not just correctly modelling another organism's mind but experiencing as negative stimuli the representations of their negative stimuli - is present only within the forms of life heavily reliant on social organization and care. Meanwhile, the ability to enjoy the sight of an enemy's body not being able to work as intended, or even to just enjoy playing with food, is useful all round.

I do feel that this form of perverse empathy exists on such a foundational level that it can easily slip past conscious thought in the absence of highly-developed self-awareness. Psychopaths tend to enjoy harming people in creative, distinctively cruel ways, yet on intellectual level they tend to report not being able to understand how their actions make their victims feel. 

It's no more reasonable to ask a person not to use an enjoyment-generating faculty they posses than to ask them never to use this or that body part. Yet it is always reasonable to ask a person not to unjustly inflict pain. Of course, there are ways around this, but most of them are unhealthy, and still cruel. The ones that aren't cruel are packaged in ways only truly understandable by self-aware people, who don't have as much problem being instinctually cruel to begin with. I guess the path forward is to just insist on more self-awareness from everyone. This is just another facet of the shared, uncomfortable darkness that we have to tame.

 * I'm usually not like this, except secretly in my head all the time