“I said that I would do almost anything to support my wives and kids—and I have; I have shoveled human excrement for a pittance, standing in it up to my knees, rather than let a child go hungry. But this I will not touch. Nor is it because I was once a slave myself; I have always felt this way. Call it a ‘belief’ or dignify it as a deep moral conviction. Whatever it is, for me it is beyond argument. If the human animal has any value at all, he is too valuable to be property. If he has any inner dignity, he is much too proud to own other men. I don’t give a damn how scrubbed and perfumed he may be, a slaveowner is subhuman.”
– Robert Heinlein, Time Enough For Love