Causal powers exclusion argument

Ned Block, in his article Do Causal Powers Drain Away , puts forth a powerful version of the generalization argument. He argues that if Kim s exclusion/supervenience argument is sound, then we are left with two unappealing, and presumably false, consequences. First of all, if the exclusion principle is true, then causation at any irreducible supervenient level will always be pre-empted by causation at a subvenient level below it. Furthermore, if matter is infinitely divisible, and there is no lowest level, then we will be left with no causation anywhere. Kim refers to these two... 

So it seems that in this scenario, where we have closure at L - 1 with respect to L, the exclusion principle and seepage will both apply. The causal powers of properties at L will always be preemped by properties at L - 1. Causation need not seep down to a lowest closed level for the exclusion argument to work. Instead, it seems that if the exclusion principle applies to all irreducible supervenient levels, then whenever there is closure of a subvenient level with respect to its supervenient level, causation will seep... 

Microbased properties are supposed to be immune from the exclusion argument. Why Fundamentally, because they represent novel causal powers, novel relative to the causal powers of their constituent properties and relations. Recall the conclusion of the passage quoted earlier ... 

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