People of relatively low intelligence can be morally wonderful if they desire the right and the good (not necessarily under the description "right" or "good"). Their low intelligence sometimes results in their accidentally doing something wrong, but doing something wrong out of low intelligence alone is like stepping on a person's foot because you are (literally) blind or missing a cry for help because you are (literally) deaf. We do not judge the blind or deaf person as morally bad.
Nomy ArpalyThe fact that only humans above a certain age can be morally virtuous, rather than babies or cats, means that that being moral requires some cognitive ability. If virtue is about desires, it is worth remembering that you can't desire some things without being able to conceive of them. Suppose a virtuous person will desire to make people happy and desire to tell the truth. You can't desire to make people happy without having the concept "happy" and you can't desire to be truthful if you don't have have the concept "lie", so a cat or a baby cannot desire these things.
Nomy ArpalyI would be ok if I found out for sure that if I am in any way superior to a wolf it is simply in virtue of my brain's higher capacity and complexity. A large difference - my cerebral equipment allows me to have such diverse concepts as "hope", "funky", "England", "multiplication", "three strikes" and "the categorical imperative" - but a difference in degree. Wolves, of course, are superior to me with regards to smelling, hearing, and running, and are generally superior to humans in that they don't kill each other.
Nomy ArpalyIf I make a stupid decision but don't execute it because I'm, say, lazy, then I'm lucky, not rational. However, at other times a person acts for good reasons just as she does what she thinks she shouldn't do, not knowing that they are good reasons. Just like sometimes we are a lot less rational than we think we are, it is also true that sometimes we are a lot more rational than we think we are.
Nomy ArpalySometimes we deliberate - for example when we plan a long trip or - if we are not math wizards - when we solve long division problems. However, if we deliberated every time we acted we would never get through the day. Most of the time, we act for reasons without deliberation. I am not just talking about cases of simple, habitual action, like brushing your teeth, but also about more sophisticated action.
Nomy ArpalyI don't think we are all irrational every time we fail to see through an argument in a book, but suppose it's true about you. You are still more rational than you think you are. You are irrational in a minor way - believing a misguided theory of the nature of rationality - but rational in a major way - you respond well to probabilistic evidence as you go through the day.
Nomy Arpaly