Didn't the whole time travel involve a paradox?
Its been years since I seen the movie so correct me if I wrong
Isnt the only reason he kept a diary was because he suffered black outs which was caused by his future self reading the diary
He suffered a black out and writes about it because he was told to and then years later reads the diary entry which caused the black out
Isn't this some kind of grandfather paradox where instead of killing your grandfather you save your grandfather when he was a baby