“The idea of a law of progress, or of an all but irresistible tendency to general improvement, is then merely a superstition, one of the tents of the modernist pseudo-religion of humanism. Even if such a law or tendency existed and were demonstrable, the liberal faith in progress would for Santayana be pernicious. For it leads to a corrupt habit of mind in which things are valued, not for their present excellence or perfection, but instrumentally, as leading to something better; and it insinuates into thought and feeling a sort of historical theodicy, in which past evil is justified as a means to present or future good. The idea of progress embodies a kind of time-worship (to adopt an expression used by Wyndham Lewis) in which the particularities of our world are seen and valued, not in themselves, but for what they might perhaps become, thereby leaving us destitute of the sense of the present and, at the same time, of the perspective of eternity.”

Source: The Anatomy of Human Destructiveness (1973), p. 264

The Architecture of Theories (1891)
Context: The origin of things, considered not as leading to anything, but in itself, contains the idea of First, the end of things that of Second, the process mediating between them that of Third. A philosophy which emphasises the idea of the One, is generally a dualistic philosophy in which the conception of Second receives exaggerated attention: for this One (though of course involving the idea of First) is always the other of a manifold which is not one. The idea of the Many, because variety is arbitrariness and arbitrariness is repudiation of any Secondness, has for its principal component the conception of First. In psychology Feeling is First, Sense of reaction Second, General conception Third, or mediation. In biology, the idea of arbitrary sporting is First, heredity is Second, the process whereby the accidental characters become fixed is Third. Chance is First, Law is Second, the tendency to take habits is Third. Mind is First, Matter is Second, Evolution is Third.

Source: Words of a Sage : Selected thoughts of African Spir (1937), p. 57.

Source: Autobiography (1873)

https://archive.org/details/autobiography01mill/page/42/mode/1up p. 42

The Roots of American Order (1974)

Zoönomia, vol. 1 (1794).

[The mysteries within: a surgeon explores myth, medicine, and the human body, Simon & Schuster, 2001, 18, https://books.google.com/books?id=uSBaTVMTYvIC&pg=18]
The Mysteries Within (2000)

Source: Moon Over Soho (2011), Chapter 4, “One-Tenth of My Ashes” (p. 64)