Ah, the good old days! In the good old days, for an afternoon’s entertainment, you and your friends might nail a cat to a stake and take turns ramming it to death with your head. Someone might lose an eye in the process, but what fun! Or you could watch a neighbor flogging his slave, admire the dead bodies strung up on the gallows (in case you missed the hanging), torment the people in stocks, or listen to the lady next door beating her servant. Then it’d be time for dinner; if you were effete and unafraid of ridicule, you might eat with a fork, but otherwise, eat with your fingers and knife, and wipe your fingers off on your shirt. When you have gnawed the meat off the bone, just drop the bone on the floor for the dogs to eat. When dinner was finished, the garbage was just flung into the open sewer in front of your house, and you abided with the stench. The pigs wandering the neighborhood would eat some of the garbage, and the rest might get washed away in a rain. You stayed in your hometown. You had no place to go, really, because travel was not only difficult but downright dangerous, with bandits eager to cut your throat for your purse, and trying to stay off the gallows. Of course you could go to the gallows yourself if you stole a handkerchief or got hungry and swiped some bread. If your child showed “strong evidence of malice” between the ages of seven and fourteen, they could be hanged, too. If the king didn’t like your religious practice, you might be burned to death, and friends and neighbors would come to watch and jostle for positions downwind so they could get a whiff of your burning body, to sanctify themselves.
Doesn’t that sound just great?
No. We have moved forward, fighting step by step. Before I go any further, I assume that my reader would not wish to be on the receiving side of such events: you would not like to be enslaved, do not think it’s nice to nail cats to stakes, think sanitation is a good thing, would not like to see your neighbor burned to death just because he is a Baptist, enjoy going off on vacation without worrying about getting your throat cut, and so forth.
Now normal people consider the events detailed in the first paragraph inhumane, but at the time (I am basing this description roughly on life in medieval London, although there were not African slaves yet), they were taken for granted.
Every step forward has been achieved only by the hard work of people who were not willing to accept those practices, striving in the face of fierce resistance of those who thought the old ways were just fine.
The people who have achieved these advances are called “liberals.” The people who oppose these advances are called “conservatives.” Issues liberals fight for are taken for granted fifty years later, and after another fifty years, when some issues may well be out of date, they are strongly defended by conservatives.