Directionality and Differences Between Theories

none of the relations offered in the literature (and I am not aware of another candidate) adequately captures the reductive link . None of them makes sense of the directionality of reduction. Instead, we should, in the spirit of Holism, take a look at other features of entire theories that could give rise to the directionality of reduction. Reduction reconciles diversity and directionality with unity. Why not tie diversity to differences between pairs of reducing and reduced theory  

Under these conditions the old theory reduces to the new. When reduction is successfully achieved, the new theory will explain the old theory, it will explain why the old theory worked as well as it did, and it will expltiin much where the old theory was buffaloed (1986,283) 

Churchland seems to suggest that the directionality derives from the concept of reduction I take this to suggest that in virtue of the reductive link, we will expect the reducing theory to explain the old one and so forth. Thus, these explanation-relations enter the game in virtue of reduction, such that we should not expect the reduction model to be (illuminatingly) definable via ejfects of the instantiation of a reduction relation. Based on the non-holistic model of reduction developed in Chap. 5, we will be in a position to argue against holistic approaches as follows On the non-holistic account developed here, we can in fact account for why we should expect at least some cases of reductions to exhibit these features. On the holistic account, these features are left unexplained. An explanation is called for, and any notion of reduction that yields such an explanation is more fundamental than the holistic one. 

Before turning to this argument in Sect. 8.7, let me, firstly, argue that conditions (6) and (9) miss the target (8.4). In a second step, I will show that all of these criteria fail, if possibly, there exist relevantly equivalent theories that may instantiate the reduction relation (8.5). Thirdly, I will show that even if we were able to come up with a coherent holistic account of reduction, we would still have to account for reduction in terms of exactly those semantic and metaphysical properties we have referred to within the ontological account proposed in the first part of this book. Thus, holistic approaches do not come cheaper in this respect (8.6). 

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