How did European powers justify the establishment of slavery?

European powers justified slavery through economic necessity, racial superiority theories, and religious and civilising missions.

European powers, particularly Portugal, Spain, Britain, France, and the Netherlands, justified the establishment of slavery primarily on the grounds of economic necessity. The discovery of the New World in the late 15th century led to the establishment of colonies that required a large workforce to exploit the vast resources. The indigenous populations were often insufficient or unwilling to provide the labour needed, leading to the importation of African slaves. The economic argument was that the prosperity of Europe, and by extension, the civilised world, depended on the exploitation of these new territories, and slavery was seen as the most efficient way to achieve this.

Theories of racial superiority also played a significant role in justifying slavery. Europeans considered themselves superior to other races, particularly Africans, whom they viewed as uncivilised, primitive, and inherently suited to servitude. This belief was often reinforced by pseudoscientific theories that sought to categorise and rank races based on perceived physical and intellectual differences. The racial argument served to dehumanise Africans, making it easier for Europeans to justify their enslavement.

Religion was another significant factor used to justify slavery. Many Europeans believed that they had a divine mandate to convert non-Christians to their faith. Slavery was seen as a means to this end, with the assumption that enslaved Africans would be exposed to Christianity and thus saved from eternal damnation. This religious justification was often intertwined with a civilising mission, where Europeans saw themselves as bringing progress and civilisation to 'backward' societies.

Finally, legal and philosophical arguments were also used to justify slavery. European legal systems often did not recognise the rights of non-Europeans, and philosophers such as John Locke argued that slavery was a legitimate form of punishment for certain crimes. These arguments provided a veneer of legitimacy to the institution of slavery, reinforcing the other justifications and making it easier for Europeans to reconcile the practice with their self-image as enlightened and civilised societies.