I've been reading a bit about systems science/theory and I understand that in some fields it sometimes pays off to look at how the whole systems behave as opposed to how the individual parts that comprise the systems work. However, there seems to be a certain aspect of systems theory known as "downward causation". This is defined as (from Wikipedia): There are also claims that because of this you could never simulate the system by simulating the parts and their interaction without considering this "action" (or force? I don't know what the right word is) that the system supposedly exerts on its parts. My knee-jerk reaction was that this is nothing but crackpottery. I have tried to find some mainstream hypotheses or experiments supporting such an idea but I only found philosophy stuff, which has neither. So, my question is: are there any hypotheses and/or experiments described in mainstream science literature that support this seemingly absurd idea of "downward causation" or is it just crackpottery?