Lewis’s “The Paradoxes of Time Travel”

Lewis starts out considering time travel that involves two time dimensions. What does Lewis think about this way of making sense of time travel?

What are external and personal time? Others have said that it makes no sense to say that in five minutes from now this time traveler will be in the distant future. How does Lewis make sense of this talk using the distinction between external and personal time?

It is easy to miss Lewis’s point about what a time traveler can or can’t do. According to Lewis, can I travel back in time and kill my grandmother before she gave birth to my mother?

Lewis talks about two different ways one might be said to change a moment. What are the two different ways?

What does it mean to say that I can skip a stone, according to Lewis? He says that ‘certain facts’ come into play in the determination of whether someone can or cannot do something. Explain what would make some fact one of these ‘certain facts’.