Three Conundrums Inspired by a Second Viewing of Tenet

Conan’s Apartment

Conan enjoys hosting and entertaining guests at his apartment. When they are around, Conan is a happy person. 

However, one of Conan’s friends, Semaj, is concerned because he believes that when there are no guests in Conan’s apartment, Conan is very sad. Semaj also believes that when guests arrive, Conan forgets his sadness and is only happy. 

In order to help his friend, Semaj comes over early one day to confront Conan. Conan is happy to see his friend. Semaj tells Conan, “I am concerned about your happiness, so don’t lie to me.” Conan agrees. (Conan is an honest person and never lies.) Semaj then asks, “I know that you are happy now, but before I entered your apartment, were you sad?”

Can Semaj believe Conan to tell the truth about whether he was happy or sad? Was Conan truly happy or sad before Semaj arrived?

The Tenet Enjoyment Quandary

After Conan and Semaj finish their discussion, they agree to watch a movie. Conan wants Semaj to watch the movie Tenet. Semaj has not seen it. Conan has already seen it and believes that Semaj will like it if he watches it.

Conan wants Semaj to enjoy the movie as much as Conan enjoys the movie. However, people who like Tenet like it half as much more upon an additional viewing of the entire movie, and Semaj will only watch the movie if Conan watches the movie with him. 

Will Semaj ever enjoy Tenet exactly as much as Conan? If so, how many times must Conan watch Tenet with Semaj for them to enjoy the movie equally?

Inverted Message from the Future

After watching Tenet, Semaj learns about temporally inverted objects. The next day, Semaj receives a temporally inverted message from his future self. The message simply says, “Save more.” 

Semaj spends his life living frugally and saving so that he can achieve financial independence and retire early. Semaj is now concerned about his future security. However, he is also worried about enjoying the present too. He knows that if he sacrifices more now, his future self might be more secure and more happy, but his present self will be less happy due to the increased fiscal austerity.

Does Semaj trust the advice of his future self and believe that he can alter the future in order to ensure more security? Or does he accept that no matter how much he saves he cannot change the financial insecurities of his future self? What should Semaj do?