Becoming an angry atheist

[dyresand]

Efficient causes necessarily entail final causes. In order to define the start and end point of cause-effect relationship you necessarily invoke the function or purpose achieved by the sequence of events.

No. A landslide may have an efficient cause (rainfall softening the substrate), but there is no purpose behind it, unless you assume that some deity wishes to kill a few hundred people while rearranging the garden. Invoking purpose into the equation is assuming what you wish to demonstrate -- that there is a purposeful actor, which you call "God". This is circular reasoning, as you well know.

Besides, you still haven't answered my question as to how an immaterial being might affect material reality. I'd like an answer for that, please.

well one would have to guess is what is god first. he wouldn't look human.. though if he was real he would manifest in a human like being.