It is God alone that can pronounce upon the real condition of the heart and soul, out of which are the issues of life. A true phrenological fact, therefore, which we can force a sound mind to believe must involve, in one of its aspects, a species of knowledge which ist is not in the power of man, and still less within his province, to attain; and in the other, a physical fact, which can be seen only in the brain itself, and which cannot be interfered from any external sign.

Review of Vestiges (1845)