How does Crusoe's actions on the island reflect the society of Britain in the 18th century?
Defoe's 'Robinson Crusoe' was published in 1719, in the second decade of the 18th century in England/Britain. In a number of ways, according to scholars and critics of this work, the novel reflects some aspects of English/British society/social development at that time, in particular via Robinson Crusoe's activties/actions on the island when he is a castaway.
While it would be tedious to give a very long answer in detail, about these aspects, and Im sure that with a little research and by refering to the text of the book itself you can find examples of each of these, basically these main aspects of British/English society/social beliefs and development/s are notable:
1. Colonial-- Britain was expanding its new-founded colonial possessions (which would reach full maturation in the 19th c) and its colonial administrators, colonists etc were in fact going all over the world precisely like Crusoe, 'settling' remote places.
2. Religious-- British society was still a religious one at that time, despite the growth of science and scepticism and slow decline of faith as the 'age of reason' soon began; and part of the 'colonizer's mission' was to bring (what was believed to be) the 'superior' virutes of Christianity to 'pagans' and 'savages', according to teh ideas of the time.
3. Moral-- linked to the above point, was the morality of Christianity, as practiced by British colonizers, who felt themselves to be more pious, virtuous and 'better' than other people/s whom they deemed savages; and it was also an imperative in their society at that time to introduce 'Christian moral virtues' to these remote/savage societies to relace their traditional ways and customs that were considered 'backward' and 'primitive' etc--a judgmental attitude.
4. Economic--the 18th c in Britain/Engand was one of many economic theories and of economic exopansionism, of the start or earliest inception of industrialization etc: and Robinson Crusoe is also shown as an innovative, 'productive' capitalist, 'developing' the island ('his' island now) for maximum benefit.
These are the basic points and hope are helpful. Please refer below for aditional links etc.