I bet that in a thousand years from now we will consider life as anything having a)enough presence of nonequilibrium thermodynamics states, and b)the ability to perform universal computation (either classical or quantum, or maybe another yet undiscovered more general thing). This could include, as foreseen by Asimov, lakes of superconducting metals in remote planets. Will vegetarianism in the future include moral attitudes for superconducting helium inside high field magnets? Will we see an invasion of Earth by superconducting metal intelligent beings on a hunt-those-superconducting-torturers/bastards?
Maybe in Pluto there is a colony of intelligent robots (which communicate through gravity waves, i.e. civilizations withouth a theory of quantum gravity wouldn't detect their communications) and they are waiting for our civilization to build enough autonomous electronic components, so that at a given point they will send a signal/virus, take control of all our electronic infracstructure and take on planet's control. The threats of civilization always come from possibilities that we weren't able to imagine.
photons have size and mass
arrgggghh! I thought photons didn't have mass and this was the reason why they could travel at light's speed (apart from a small effective mass coming from virtual electron-positron pairs creation along propagation). When I heard the sentence, in the background there was a violin string breaking too.
Some people who see an animal experience pain tend to identify with, "empathize" with it, and commit anthropomorphic fallacies.
Substitute "animal" by "negro" in your sentence and much enlightenment will come to you (hopefully, otherwise go for easier mental goals).
While it is not logical to empathize with other beings (why should I suffer because of others?) it is "human" to do so. You can check the definition of psycopathy, for example.
In my experience with these creatures, I have not seen any evidence of sentience. They have no ability to behave outside of instinct, and insofar as I can tell, memory is only established through repetition.
I know a percentage of the population in my country can be classified according to that. Furthermore, ALL countries behave like that (macropsychology). Have you ever seen a human behaving outside of instinct? I very much doubt you can give me any example of that. I bet on it.
Now, seriously, it's a matter of sensitivity for other being's suffering. Yours doesn't reach the level where you imagine the suffering of cows/chicken. It's not something debatable, it's something you either are able to feel or not. I'm sorry for people like you.
The world is moving so fast these days that the man who says it can't be done is generally interrupted by someone doing it. -- E. Hubbard