While I was daydreaming in my boring math class today I came across a weird problem. What ACTUALLY causes a wave function to collapse. I had a discussion with my teacher the week prior and she was telling me that it has something to do with your brain. I didnt really believe her, I just thought it was something that everyone had to accept, however, during my daydream I had the idea that the interactions between photons and objects forces wave function collapse. If that makes any sense. Photons have really small mass, and if they act as a particle and smack into objects at c wouldnt that in some way change the object?! [In this case force it to collapse?] This may be a really silly question but I am only basing this off of my limited knowledge of QM.