The great leading division of the mental phenomena which has met with most general adoption by philosophers, is into those which belong to the _understanding_, and those which belong to the _will_;--a division which is very ancient, but though sanctioned by the approbation of many ages, very illogical; since the will, which, in this division, is nominally opposed to the intellect, is so far from being opposed to it in reality, that, even by the asserters of its diversity, it is considered as exercising, in the intellectual department, an empire almost as wide, as in the department allotted to itself. We reason, and plan, and invent, at least as _voluntarily_,--as we esteem, or hate, or hope, or fear. How many emotions are there too, which cannot, without absolute torture, be forced into _either_ division! To take only a few instances, out of many,--to what class are we to reduce grief, joy, admiration, astonishment, which perhaps are not phenomena of the mere understanding, and which,--though they may lead indirectly to desires or volitions,--have nothing, in themselves, that is voluntary, or that can be considered as in any peculiar degree connected with the _will_? The division of the mental phenomena into those which belong to the _understanding_, and those which belong to the _will_, seems, therefore, to be as faulty, as would be the division of animals, into those which have legs and those which have wings; since the same animals might have both legs and wings, and since whole tribes of animals have neither one nor the other.