casuistry

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Specious or excessively subtle reasoning intended to rationalize or mislead.
• noun The determination of right and wrong in questions of conduct or conscience by analyzing cases that illustrate general ethical rules.

from The Century Dictionary.

• noun In medicine, a recent, rare, and improper use for casuistics.
• noun In ethics, the solution of special problems of right and duty by the application of general ethical principles or theological dogmas; the answering of questions of conscience.
• noun Hence Over-subtle and dishonest reasoning; sophistry.

from the GNU version of the Collaborative International Dictionary of English.

• adjective The science or doctrine of dealing with cases of conscience, of resolving questions of right or wrong in conduct, or determining the lawfulness or unlawfulness of what a man may do by rules and principles drawn from the Scriptures, from the laws of society or the church, or from equity and natural reason; the application of general moral rules to particular cases.
• adjective Sophistical, equivocal, or false reasoning or teaching in regard to duties, obligations, and morals.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The process of answering practical questions via interpretation of rules or cases that illustrate such rules, especially in ethics.
• noun pejorative A specious argument designed to defend an action or feeling.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun moral philosophy based on the application of general ethical principles to resolve moral dilemmas
• noun argumentation that is specious or excessively subtle and intended to be misleading