Oh! So the subgroups are being considered as elements rather than as systems, and condition 3 is actually saying that every set of elements (other than the whole system, I assume) is affected by something outside itself? (Equivalently, however you partition the elements into two partitions there are influences flowing both ways across the boundary.)
You’re right: that’s a much more sensible definition, and I retract my claim that Ackoff’s definition shows bad thinking. I maintain, however, that it shows bad writing—though perhaps in context it’s less ambiguous.
That last quotation, though. At first glance it nicely demonstrates that he has “your” reading in mind rather than “mine”; good for him. But look more closely at the last sentence. “No subset of elements is unrelated to any other subset”. In particular, take two singleton subsets; his condition implies once again that every element is “related to” every other. So maybe I have to accuse him of fuzzy thinking again after all :-).
Oh! So the subgroups are being considered as elements rather than as systems, and condition 3 is actually saying that every set of elements (other than the whole system, I assume) is affected by something outside itself? (Equivalently, however you partition the elements into two partitions there are influences flowing both ways across the boundary.)
You’re right: that’s a much more sensible definition, and I retract my claim that Ackoff’s definition shows bad thinking. I maintain, however, that it shows bad writing—though perhaps in context it’s less ambiguous.
That last quotation, though. At first glance it nicely demonstrates that he has “your” reading in mind rather than “mine”; good for him. But look more closely at the last sentence. “No subset of elements is unrelated to any other subset”. In particular, take two singleton subsets; his condition implies once again that every element is “related to” every other. So maybe I have to accuse him of fuzzy thinking again after all :-).