Wave function collapse is a causal event.
you: What is the cause if I may ask?
The creation of a fictional story is a causal event. As the observer I would say the will of Sir Arthur Conan Doyle is the cause, and the character of Sherlock Holmes is the effect. Pen and paper would be material causes under Aristotle's definition, i.e. but for pen and paper there would be no Sherlock Holmes.
Also as the observer, I would say that photosynthesis is a causal event, with the photon as the cause and the organic compound as the effect. Carbon dioxide is a material cause in photosynthesis.
If I were an observer favoring the Copenhagen interpretation of quantum mechanics, I would say that an observation (whether by intelligent or non-intelligent agency) is the cause of a wave function collapse, the event and the effect.
However if I were an observer favoring an objective collapse theory of quantum mechanics, I would say the collapse is independent of the observation, the result of a physical threshold being met and thus the cause is the threshold being met (involuntarily) and the wave function collapse the event and the effect.
As an observer of the "lofty structure of all that there is" (as Einstein termed it) - I testify that the will of God The Creator is the cause, "Creation Week" is the causal event and "the lofty structure of all that there is" is the effect.
However if I were an observer favoring an objective collapse theory of quantum mechanics, I would say the collapse is independent of the observation, the result of a physical threshold being met and thus the cause is the threshold being met (involuntarily) and the wave function collapse the event and the effect.
Penetrating insights here, dearest sister in Christ!
RE: the "objective collapse theory," I get the strange impression that Richard Feynman has attempted to model this with his path integral formalism. It seems to me that he has taken very great pains to obviate any role for the observer. But then, it turns out that, without the observer, "I can safely say that no one understands quantum mechanics. So do not keep saying to yourself, if you can possibly avoid it, 'but how can it be like that?' Nobody knows how it can be like that." [from: "The Character of Physical Law," (Messenger Lectures, 1964, by Richard Feynman {2001}).]
But Feynman describes "the threshold being met" as calculatable by summing all possible paths....
But how does he/we know what paths/how many paths are possible?
But that's an epistemic problem, I suppose — a problem relating to "understanding." I know of many scientists nowadays who don't care so much about understanding things — what they care about is that scientific formalisms/theories actually work in scientific applications. And it turns out that the path integral formalism does work. (We just don't know why; and as Feynman admonishes, we shouldn't even ask.)
Of course, I am always interested in the "Why???" question!
Thank you ever so much, dearest sister in Christ, for your outstanding essay/post!