- Christianity is more than history; it is also a system of truths. Every event which its history records, either is a truth, or suggests a truth, or expresses a truth which man needs to assent to or to put into practice.
- Reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895), p. 133.
- Spencer "was incapable", our critic haughtily re marks, "of discerning the difference between a homogeneity in matter, necessarily and blindly tending toward a heterogeneity, , and such a law of organism [sic], progress, and growth as requires a spiritual intelligence to originate and maintain it." Perheps he was a poor man! or perhaps he thought he had better discern and formulate progress where he could do it to the best advantage, and leave the postulating of spiritual intelligences to those who had a greater talent than he for building in the region of the unverifiable.
- Porter (1886) "Ex-president Porter on Evolution" in: Popular Science. Sept 1886. Vol. 29, nr. 37. p. 589.
- Civil Liberty: A Sermon, from the Antislavery Literature Project
- The Human Intellect: With an Introduction upon Psychology and the Soul via Google Books.
- Peirce, C. S. (1869), "Professor Porter's Human Intellect" (review), The Nation 8, 211-13 (March 18, 1869). Peirce Edition Project Eprint.