scholarly journals Constructive Empiricism and the Closure Problem

Erkenntnis ◽  
2011 ◽  
Vol 75 (1) ◽  
pp. 61-65
Author(s):  
Guillaume Rochefort-Maranda
1978 ◽  
Vol 69 (10) ◽  
pp. 4617-4620 ◽  
Author(s):  
R. F. Kayser ◽  
H. J. Raveché ◽  
W. W. Wood

Author(s):  
J. S. Shrimpton ◽  
S. Haeri ◽  
Stephen J. Scott
Keyword(s):  

1994 ◽  
Vol 1 (30) ◽  
Author(s):  
Thore Husfeldt

We give an algorithm for the Dynamic Transitive Closure Problem for planar directed acyclic graphs with one source and one sink. The graph can be updated in logarithmic time under arbitrary edge insertions and deletions that preserve the embedding. Queries of the form `is there a directed path from u to v ?' for arbitrary vertices u and v can be answered in logarithmic time. The size of the data structure and the initialisation time are linear in the number of edges.<br /> <br />The result enlarges the class of graphs for which a logarithmic (or even polylogarithmic) time dynamic transitive closure algorithm exists. Previously, the only algorithms within the stated resource bounds put restrictions on the topology of the graph or on the delete operation. To obtain our result, we use a new characterisation of the transitive closure in plane graphs with one source and one sink and introduce new techniques to exploit this characterisation.<br /> <br />We also give a lower bound of Omega(log n/log log n) on the amortised complexity of the problem in the cell probe model with logarithmic word size. This is the first dynamic directed graph problem with almost matching lower and upper bounds.


2018 ◽  
Vol 25 (2) ◽  
pp. 562-587 ◽  
Author(s):  
Adam R C Humphreys

Discussions of causal inquiry in International Relations are increasingly framed in terms of a contrast between rival philosophical positions, each with a putative methodological corollary — empiricism is associated with a search for patterns of covariation, while scientific realism is associated with a search for causal mechanisms. Scientific realism is, on this basis, claimed to open up avenues of causal inquiry that are unavailable to empiricists. This is misleading. Empiricism appears inferior only if its reformulation by contemporary philosophers of science, such as Bas van Fraassen, is ignored. I therefore develop a fuller account than has previously been provided in International Relations of Van Fraassen’s ‘constructive empiricism’ and how it differs from scientific realism. In light of that, I consider what is at stake in calls for the reconstitution of causal inquiry along scientific realist, rather than empiricist, lines. I argue that scientific realists have failed to make a compelling case that what matters is whether researchers are realists. Constructive empiricism and scientific realism differ only on narrow epistemological and metaphysical grounds that carry no clear implications for the conduct of causal inquiry. Yet, insofar as Van Fraassen has reformed empiricism to meet the scientific realist challenge, this has created a striking disjunction between mainstream practices of causal inquiry in International Relations and the vision of scientific practice that scientific realists and contemporary empiricists share, especially regarding the significance of regularities observed in everyday world politics. Although scientific realist calls for a philosophical revolution in International Relations are overstated, this disjunction demands further consideration.


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