Equiano addresses prejudices that suggest the black skin colour of Africans was a natural indicator of their inferiority:

Let the polished and haughty European recollect that his ancestors were once, like the Africans, uncivilized, and even barbarous.  Did Nature make them inferior to their sons? and should they too have been made slaves? Every rational mind answers, No. Let such reflections as these melt the pride of their superiority into sympathy for the wants and miseries of their stable brethren, and compel them to acknowledge, that understanding is not confined to feature or colour. (Equiano 45)