Scientific racism emerged to justify slavery once religious justifications failed

Evidence

In the same way, in the 18th and 19th centuries, Europe developed a pseudo­ science and and a pseudo-philosophy, the purpose of which was to justify the enslavement of the Blacks in intellectually acceptable terms, according to the standards of the time. One could no longer say that it was the will of God, nor could one simply exercise the rights of the conqueror over the conquered, as would have been normal in earlier times, and was still normal in some parts of the world. Something that looked philosophical, better still scientific, was needed to justify and ideologise exploitation on the hand, and primitive hatred on the other. — Bernard Lewis, From Babel to Dragomans, 1041

Categorization

• XREF: Connects to the broader literature on how ideologies are retrofitted onto preexisting exploitation (cf. Milgrom on institutions emerging to solve problems). — connects to: Theology justified slavery and genocide by marking whiteness as Christian — Andrew L. Whitehead, American Idolatry, 145; Scientific racism followed from placing humans in the animal kingdom; Eighteenth century ethnology secularized racism into a scientific ideology justifying conquest. (+1 more)
• SEED: An essay angle: the debt of modern scientific racism to the collapse of religious justifications for slavery — ideology as always catching up to justify material practice.