Are humans the only species that has the ability to reason? The answer, I guess, is who knows? First, we don't really know what is going on in the heads of individuals in species that do not write or talk. Second, it isn't clear what reason means. So, unless we know what it is, how can we know that we are capable of doing it?
Reason may be related to predicting the future; we are, after all, a species that understands past, present, and future.
This seems to hold true when you google the word reason. You find arguments against sexual rstraint, against ideas of creation (which fundamentally is anti-religion--why argue against non-testable hypotheses?), against the war on drugs... One thing this seems to imply is that IF we allow people to do what makes them happy, if we encourage them to indulge in or savor the sensory, then the country will thrive. We see, thus, many more arguments about sexual freedom. Any ideas of sexual restraint are seen as ridiculous, even though every known society has placed limits on sexual intercourse. Marriage--or limiting the number of the partners can have at one time--is such a rule.
My guess is that at one time, reason was based on precedent--using precedent to understand future outcomes. When our "forefathers" tried to design the structure of the US government, they used history or precedent. Tribal law, if law is the correct term, is about following precedent. It is based on the assumption that things that worked in the past, in preventing disharmony and conflict, would also be good today.
We no longer have any faith in the past, because we feel that, in many cases, it took away our important freedoms. This was because we (thanks to psychology--the "helping" sciences) led us to believe that if we are happy, then the country will be happy. We thought we could do better and reason seened to be the best way to get there.
If we looked over history, one has to ask how often reason got people into hot water, rather than solving, in the long-term, the problem that the reason addessed. If this is true, than reason may be what destroys us all in the long run. It may not be, after all, our salvation.
