I've always had this "holier-than-thou" attitude: I don't do meat because I reckon killing an animal causes it pain. And since, in general, the average living thing tends to avoid pain as much as possible - pain must be, well, painful to say the least. So, I don't do beef, I don't do chicken - or any other meat for that matter.
But the average roach that encounters me gets the under-side of my shoe, inevitably. I have an obsession with killing ants and other insects that bite. I would kill a bed-bug if I ever saw another (something I seriously wish I won't). In other words, if insects were human (which they, thankfully, are not) then most of humanity would be in my firing line.
Does one sense a certain double standard somewhere? Well, I did - so I did some reading up.
Causing a living thing a sensation of pain is what I want to avoid - and it turns out that in order to experience pain (pain as we know it), one needs a central nervous system - something that insects apparently do not possess. (A rather dumbed down explanation of the same can be found here.).
Which gets me thinking on a tangent: an insect is little but a robot: it does what it is programmed to (by evolution, so to speak).
Which eerily corroborates what I had been thinking all along: even humans are little but over-rated robots - after all, consciousness is an illusion that the conscious mind creates to "explain" itself.
At this point I see a roach crawl on the floor. I am taking a shoe out of the closet right now. I have the shoe on my hand. The shoe is being used to crush the roach with lethal force right now. After hearing a convincing "crunch" sound, one is sure that the roach is no more. But I am not a sinner. Killing the roach was as much an ethical crime as, well, breaking a pen.