Synderesis

Synderesis (/ˌsɪndəˈriːsəs/) or synteresis, in scholastic moral philosophy, is the natural capacity or disposition (habitus) of the practical reason to apprehend intuitively the universal first principles of human action.[1]

Reason proceeds from the understanding of previously known truths (premises) to the statement of a proposition (conclusion) whose truth follows necessarily from the premises by demonstration(syllogism). The point of departure of human reasoning must be some immediately knowable, i.e. self-evident, propositions called first principles, whose truth is grasped by intuition, not demonstration.

The habit or disposition that allows the speculative reason to apprehend intuitively the principles that preside over its discursive reasoning (including non-contradiction, identity, and the excluded middle) is called "understanding of principles" (intellectus principiorum).

The capacity or disposition that allows the practical reason to apprehend intuitively the principles or laws that preside over its discursive reasoning regarding human action is called synderesis. Just as "being" is the first notion apprehended absolutely, so also "good" is the first thing that is apprehended by the practical reason, since everything that acts does so for an end which possesses the quality of goodness. The precepts of natural law can also be considered objects of synderesis insofar as all the things towards which the human being has a natural inclination are naturally apprehended by the intellect as good and therefore as objects to be pursued, and their opposites as evils to be avoided.

Synderesis is the capacity to both apprehend first principles and judge every step of the practical discourse in the light of those principles. Aas an intellectual disposition concerned with knowledge of the first principles of action, synderesis provides only the universal premise of the practical syllogism.

The notion of synderesis has a long tradition, including the Commentary on Ezechiel by Saint Jerome (A.D. 347–419), where syntéresin (συντήρησιν) is mentioned among the powers of the soul and is described as the spark of conscience (scintilla conscientiae),[2] and the interpretation of Jerome's text given, in the 13th century, by Albert the Great and Thomas Aquinas in the light of Aristotelian psychology and ethics. An alternative interpretation of synderesis was proposed by Bonaventure, who considered it as the natural inclination of the will towards moral good.

The word synderesis is by most scholars reckoned to be a corruption of the Greek word for shared knowledge or conscience, syneidêsis (συνείδησις), the corruption appearing in the medieval manuscripts of Jerome's Commentary.[3]

The term is also used in psychiatric studies, with particular reference to psychopathy.[4]