Maturity

It's a word I use a lot.
What do I mean by it?
One meaning I definitely attach to the word is the willingness to view issues from a broad perspective, to understand how actions affect not only oneself but the larger group, whatever the context. That might be one's peer group, company or society at large.
We think of infants and children as self-centered and focused on the immediate -- in both a spatial and temporal sense. Only with maturity do we begin to see the longer-term consequences and the consequences for those outside our immediate surroundings. This may develop gradually -- we may at some stage be able only to see what effect an action might have on our family, or our neighborhood, or in the next day or two.
As we mature, we are better able -- perhaps because our experiences have shown us many more consequences of many more actions -- to understand longer term and farther outward effects. And we become more understanding and tolerant of the views of others.
Given this definition of maturity, I would suggest that a liberal outlook is likely to be mature, and a conservative one generally immature.