From an email I sent to two conservative friends:
I told you once that I heard a thought provoking attempt to define progressivisn and conservatism. It proposed that progressives are guided by the urge to relieve suffering, while conservatives are guided by the urge to protect the sacred.
Thinking over this now, it still makes a lot of sense to me. And I think it helps explain why we line up in various ways on many issues.
You brought up abortion, which is a good example. And for what it's worth, I'll agree with you that it is murder, although I see murder on a continuum of degree and not as a binary. (and of course, so does the law, with its various degrees and exemptions.)
Try to imagine that you see the world with different eyes. What must be stopped is suffering. Imagine that animates you. Through those eyes, killing itself is not necessarily bad; a mercy killing of a suicidal person in pain, the (let's assume painless) killing of a fetus that is not yet viable and would likely have an unhappy life -- these in theory are reductions in suffering, so they are good or ok in progressive eyes.
Progressives do a lot of cataloguing suffering. That is why gay marriage became a progressive cause: progressives have heard many accounts of the deep pain gay people feel at being ostracized. We go see plays and watch documentaries about how some group has suffered. That alone is very different from the focus of conservatives.
It's not just caring about these things, though; progressives have the animating urge to alleviate the suffering, which makes us embrace schemes both vital and ridiculous. It also affects our relationship to the past. Where is the suffering located, temporally? Well, it's in the past. So we fetishize the future and the promise of change and experimentation to produce less suffering than in the past. Our history books are a catalogue of cruelty -- because we care especially about pain that we imagine we could alleviate, not just pain in general.
This is a deeply different world than conservatives see. To a conservative, there is a sacred core to humanity, both a universal core and a hearth in every home that too is sacred. In the conservative mind, movements to change society tend to throw the baby out with the bathwater; eg the sexual revolution did great damage by declaring modesty, chastity, prudence and shame (at lasciviousness) to be unnecessary and out of fashion. With something like slavery (I'm generalizing a lot here but trying to be fair), the conservative mind thinks, well it was obviously wrong, but it was a flawed solution to a real problem of organizing black people's lives and work, and abruptly destroying it without really addressing those problems has left many black people at sea, and they're still at sea.
Again, there's nothing inherently better or worse about the conservative lens and the progressive lens, in my opinion. What's most important is that we acknowledge their limitations and the mistakes they tend to lead to.
Eg, because conservatives aren't so drawn to stories of suffering and collective action to relieve suffering, they can really miss cases of extreme suffering. Tons of conservative statements about the past ignore the ways life sucked for people back then. You can talk about the horrors of backroom abortions, slave rape, prison rape, sexual manipulation by men in power, lynchings, destruction of black businesses, voting disenfranchisement, gay bashing, American brutality in our military occupations, etc. without having to agree with any progressive ideas about what these suggest for policy. Yet conservatives hardly ever do... with the exception of some religious figures devoted to those in suffering, in my experience. (Cf. Matthew 25:30, IIRC)
And conversely, you don't have to agree with conservative prescriptions to recognize the agony and deadweight loss of the tax code, the fundamental unfairness of compelling people to pay a huge portion of their income, the actual total percentage of income that gets paid in all direct and indirect taxes, the lousiness of the minimum wage and rent control as mechanisms for improving the lives of the poor, the positive effects of marriage and fidelity, etc. (Please add to this list, I'm not as good at listing these things than the other way around. ;-) But progressives hardly ever do.
What's most fascinating to me is the connection to relativism vs objectivism. I've asked you to consider the lesbian couple I know, and to see if you can find any sense of relief that the government is no longer going to tear one of them from their daughter. You've been silent on that, and I would guess that you don't feel curious about imagining life from their point of view. You might still do it, I'm not trying to conclude too much from that, but notice the difference in our fundamental interest in imagining that we are different people -- when you have asked me to imagine I am a business owner forced to comply with heavy regulation, I have tried to really feel the pain you are talking about.
Again, there is an unhealthy extreme to this, which happens eg when leftists go to extreme lengths to see things from the perspective of terrorists or serial killers or despots. Relativism is good at justifying all sorts of things, from Mao and Stalin's purges (I have heard this firsthand -- "The insistence on due process is a bourgeois fetish, it does the working class victims of capitalism no good") to 9/11. Susan Sontag called the 9/11 hijackers "courageous", which of course in a sense is true but which requires a degree of relativistic thinking and abandonment of support for one's tribe that you can't imagine an American conservative being the slightest bit interested in mustering.