He believed (or liked to think he believed) that when a person was in Barcelona, the people living and present in Buenos Aires and Mexico City didn't exist. The time difference only masked their nonexistence. And so if you suddenly traveled to cities that, according to this theory, didn't exist or hadn't yet had time to put themselves together, the result was the phenomenon known as jet lag, which arose not from your exhaustion but from the exhaustion of the people who would still be asleep if you hadn't traveled.
He believed (or liked to think he believed) that when a person was in Barcelona, the people living and present in Buenos Aires and Mexico City didn't exist. The time difference only masked their nonexistence. And so if you suddenly traveled to cities that, according to this theory, didn't exist or hadn't yet had time to put themselves together, the result was the phenomenon known as jet lag, which arose not from your exhaustion but from the exhaustion of the people who would still be asleep if you hadn't traveled.