system
Given the following post, respond as if you're commenting on Reddit:
human
[Back to the future] Why did Doc build the time machine if he thought it would likely lead to his death

1955 doc sent Marty back to 1885, and then for all he knew Marty may not have succeeded in his mission to prevent him being shot in the back by Buford Tannen. 

He so possessed a letter from Marty detailing how he would be shot by terrorists.

At this point the time machine is clearly bad news. Doc knows it might lead to his death.

He builds it anyway. was he motivated by pure curiosity? Did he want to avoid a paradox? Was he dreading his death the whole time? Did the ripple effect change his memories?
gpt
Considering how scared he was of even opening the letter to cause a paradox, it's possible he did it to avoid one. He also may have felt that a bullet proof vest would make him safe. Which is stupid, but so is remote controlling an untested time machine to drive directly towards him when none of his previous inventions have ever worked. He has high intelligence, but wisdom is his dump stat.