Jesuitism is a label given to particular casuistic approach to moral questions and problems often described by the adjective jesuitical, so called because it was promoted by some Jesuits of the 17th century rather than being the beliefs of the Society of Jesus as a religious order. The word seems to have been used for the first time in 1622.
Jesuitism is not a systematically developed Moral Theology school (and the word is not found in any Theological Dictionary), but some Jesuit theologians, in view of promoting personal responsibility and the respect of freedom of conscience, stressed the importance of the 'case by case' approach to personal moral decisions and ultimately developed and accepted a casuistry (the study of cases of consciences) where at the time of decision, individual inclinations were more important than the moral law itself. It has been described as an attempt to achieve holy ends by unholy means.
Blaise Pascal, the French mathematician, religious philosopher and Jansenist sympathiser, vigorously attacked the moral laxism of such Jesuits in his famous Lettres provinciales of 1656-57. It is also at odds with official Church doctrine. Although Vatican II does stress the primacy of conscience.