If he must dabble in science, keep him on economics and sociology; don't let him get away from that invaluable "real life".
In the first letter, Screwtape addresses Wormwood about a patient he has and urges him to do everything he can to better control his patient. A way through which Screwtape urges Wormwood to control his patient is through the literature he consumes and through the people he associates himself with. The quote thus highlights the idea that a person is almost always controlled by the things he sees, reads or by the people he chooses to associate himself with and thus almost none of his actions or thought are original or independent. Instead, they are all affected by some outside influence.
He leaves them to "do it on their own". And there lies our opportunity. But also, remember, there lies our danger.
In the second letter, Screwtape talks about free will and how free will is actually not something that will help them in their quest of finding as many followers as possible. Screwtape talks about how God left the men in the world the freedom to decide if they want to serve him or not and initially, this decision favored the Devil as many people chose to serve him. In time however, more and more people started to turn to Christianity again and the free will they had made it harder for the devil to tempt them. because of this, free will is portrayed negatively by Screwtape.
How much better for us if all humans died in costly nursing homes amid doctors who lie, nurses who lie, friends who lie, as we have trained them,(…)
In the fifth chapter, Screwtape writes about the war that was raging on and how it was not good for the devils because the men who found themselves on the battlefield, faced day and night with the possibility of dying were more likely to turn back to religion. For the devil, it was betters if humans stayed inside a safe place, surrounded by people lying to them and telling them that nothing bad will ever happen to them instead of being thrown in the battlefield and having to face death every day. That constant feeling of fear made many turn to religion, hoping to be saved in the event they will be killed.
