In the movie Time Machine (2002) there is a scene in which the protagonist and his girlfriend are walking in the park and the robber they meet wants to take her ring (bought for her by the protagonist). The protagonist refuses to give the ring to him which results in the robber shooting the girlfriend and killing her. After that, there is a scene where the protagonist is talking with his friend about this:
Friend: Alex, will you please stand still and look at me? It wasn't your fault.
Protagonist: No. It wasn't my fault. Maybe we should blame Mrs. Watchit for getting the ring from the jeweler. Or the jeweler for making it. Or the poor bastard who tore the stone from the earth. I should blame you for introducing us in the first place.
What philosophers argued that in a complex situation, every individual who's involved in the situation has the same value, so to speak? So, in the case above, do the faults of Mrs. Watchit, the jeweler or the poor bastard (and of all the other individuals involved in the situation, including the robber, the protagonist that had decided to walk in that park that day, etc.) have the same "size"?