Rationalists are admirable beings, rationalism is a hideous monster when it claims for itself omnipotence. Attribution of omnipotence to reason is as bad a piece of idolatry as is worship of stock and stone believing it to be God.
I do not regard flesh-food as necessary for us at any stage and under any clime in which it is possible for human beings ordinarily to live, I hold flesh-food to be unsuited to our species.