Jerry Monaco :
Yes, I mean mental structures, including the power to reason. Chimps reason.
^^^^ CB: I agree. What Chimps lack is symboling, language and culture.
They have to be rational in order to survive physically. Dogs are rational. Ants are rational. They can pursue goals , aims and achieve them. The definition of rational is to be able to pursue and achieve a goal, like catching prey or avoiding a predator.
As Marx says, the difference between the labor of humans and the labor of bees or spiders is that humans plan the job in imagination first. Imagination means symbolling.