What are some examples of enlightenment-age ideas in Robinson Crusoe?
If we understand the Enlightenment as valuing reason over received authority, privileging individual thinking and reasoning, and relying on systems of classification (including, prominently, racial classification), then the novel in many ways illustrates enlightened thought of the early 18th century (which may not, in some ways, seem "enlightened" to us).
Robinson Crusoe's religious faith will grow as a result of his island stay, but when he first becomes shipwrecked, he initially responds very rationally to his predicament, by heading out to the wrecked ship before it sinks and gathering all the supplies he can, then carefully planning and setting up his new home. Unlike in Shakespeare's The Tempest, another story of shipwreck on a deserted island, there is no supernatural presence to make sure magical deliverance occurs. Crusoe is forced to survive by his own wits and his own rational calculations. He plans for what he needs to plant, and what and where he needs to build. He uses reason and experimentation to learn to make pottery, and he finds way to keep track of time and measure out spaces. He acts as an economic rationalist, sacrificing leisure to grow barley and to dry grapes into raisins.
Even Crusoe's growing religious faith is enlightened, based on his own reason and interiority, not merely on accepting received authority from other people. As he is left for years without any human contact, he must learn to think for himself.
Finally, when Crusoe does meet and become friends with Friday, a native, the relationship is based on Enlightenment notions of race and hierarchy. While the two do become friends, the relationship is always predicated on Crusoe's sense of his superiority as a white European.
While Robinson Crusoe was written during the Age of Enlightenment, it contains largely spiritual themes as opposed to enlightenment ideas. The difference between religious enlightenment and the Age of Enlightenment is the latter's promotion of science and reason over spirituality.
Crusoe defines his stay on the island with personal responsibility and practical thinking; while he comes to a religious conversion because of his unconscious guilt (he has been very lucky in surviving, but has not given proper thanks), Crusoe takes his life into his own hands, using his knowledge and personal abilities to survive rather than trusting entirely in his new-found faith. His prior actions, taking off for the sea in defiance of his father's wishes, are typical of the anti-authoritarian enlightenment attitude, as are his mistakes in figuring out how to survive on the island.
Possibly the most significant example of Enlightenment-Age ideas is Crusoe's relationship with Friday; although they act as master and slave, Crusoe discovers that Friday is perfectly intelligent and capable of reasoning, not an ignorant savage, and they become more like friends as the story goes on. Friday's sympathetic treatment, instead of a role as unseen slave laborer, is typical of the evolving views of race relations.