Ok, so I claim to strive to be reasonable. What do I mean by reasonable?
To me, being reasonable means having a commitment to using reason to determine what makes sense, what’s appropriate, what’s true, and what’s good; and then acting in accordance with those judgments. The uniquely human abilities to understand the world, to create knowledge, to teach and learn from others seem so precious to me that it strikes me as clear that these are things to value and pursue.
Being reasonable requires being rational. This entails accepting fallibility; that none of our knowledge is certain, and is all subject to criticism. We don’t know things because the beliefs are justified in the sense of being provably true, but we should hold those theories that are the best (meaning they conform with the facts as we can observe them, have great explanatory power without unhelpful complexity, have survived the severest criticism, etc.) that we know of. We should prefer the truth to comfortable fantasies. This doesn’t mean that fantasies can’t be valuable; they can. But we shouldn’t confuse them with reality.
Being reasonable requires perspective. We should consider which factors are more important, and which are less important before we take actions. Perspective is easy to lose after spending time focusing on some aspect of a situation, or when strong emotions are involved, so we should be careful to re-evaluate how important things are as we proceed. We often need to trade-off some things in order to get others and shouldn’t let the unattainable perfection prevent us from pursuing the attainable good.
Being reasonable requires a healthy skepticism. We shouldn’t accept things as true just because they are common knowledge. Memes don’t become successful by being true and good for people; they become successful by being effective at propagating themselves. This success can happen many ways, but some of them are by exploiting mental laziness and irrationality. So, we can improve the meme pool by trying to not be mentally passive hosts and transmitters of bad ideas, but subject theories to the tests of rationality discussed above, and accept and transmit only the best theories we know of.
Being reasonable requires a good attitude towards change. Many people are overly pessimistic with respect to change. Change carries risks, but also opportunities. All progress requires change. We can try to resist it at every turn and suffer the consequences; or we can embrace it and deal with it rationally. For an amusing treatment of how to deal with change personally, see this book. For an excellent treatment of the larger societal issues related to how we deal with change, see the book promoted here.
Relationships are very important in life. Being reasonable socially entails being flexible, kind, humorous, generous (but not self-sacrificial) because acting this way makes life more pleasant, helps people reap the synergistic benefits of cooperation, overcoming initial differences in plans and expectations. We often gain by being open to pursuing a common preference rather than by stubbornly standing on our rights.
There’s a lot more to being reasonable than I’ve sketched here, but it’s a start.