Kim: In northern Europe during the eighteenth century a change of attitude occurred that found expression both in the adoption of less solemn and elaborate death rites by the population at large and in a more optimistic view of the human condition as articulated by philosophers.
Lee's Conclusion
It seems unlikely that "the dramatic increase in life expectancy" that occurred early in the 18th century explains the changing attitudes about death and the human condition throughout the 18th century.
Lee's Evidence (because)
If people aren't aware that their life expectancy has increased, then increased life expectancy couldn't change their attitude about death and the human condition.
Evaluate
One glaring assumption in Lee's counterargument is that he uses a conditional premise but never establishes the trigger.
He seems to be assuming that people of the early 18th century were not aware that their life expectancy had increased.
If we grant Lee the truth of his premise and also grant him this assumption, then his conditional logic premise guarantees his conclusion.
His conditional premise says:
While we don't usually fight premises, this seems like one we might see LSAT actually chip away at. Do people really have to be aware of their growing life expectancy in order for their growing life expectancy to change their attitudes?
Maybe I'm unaware that I have a tapeworm in my stomach that is causing me to eat more food than I normally would, but the existence of that tapeworm could still be the explanation for why my attitudes about eating have changed (sorry for the gross example).
Goal
Let's look for an answer that punches back at the Lee's assumption and suggests that people in the 18th century were somehow aware that their life expectancy had increased.
Or let's find an answer that gives us a way to argue that even if you're not aware that your life expectancy is growing, it could still be causally affecting your attitudes about death / the human condition.