In his review of Church's Thesis after 70 Years edited by Adam Olszewski et al. 2006, Peter Smith's criticism of a paper by Muraswski and Wolenski suggests 4 "lines" re the status of the Church–Turing Thesis: (1) empirical hypothesis (2) axiom or theorem, (3) definition, (4) explication. But Smith opines that (4) is indistinguishable from (3), cf Smith (July 11, 2007) Church's Thesis after 70 Years at http://www.logicmatters.net/resources/pdfs/CTT.pdf
A collection of papers can be found at Church's Thesis after 70 Years edited by Adam Olszewski et al. 2006. Also a review of this collection by Peter Smith (July 11, 2007) Church's Thesis after 70 Years at http://www.logicmatters.net/resources/pdfs/CTT.pdf
merriam-webster.com
"See also" Merriam-Webster's Online Dictionary, 11th Edition (accessed July 26, 2014), which also gives these definitions for "effective" – the first ["producing a decided, decisive, or desired effect"] as the definition for sense "1a" of the word "effective", and the second ["capable of producing a result"] as part of the "Synonym Discussion of EFFECTIVE" there, (in the introductory part, where it summarizes the similarities between the meanings of the words "effective", "effectual", "efficient", and "efficacious").
