The "Jansen" to whom Webster refers is Cornelis Jansen
, 17th-century Dutch theologian
whose teachings were deemed heretical by Pope Urban VIII
Jansen's ideas place heavy emphasis on predestination and deny the existence of free will. Jansen also taught that human nature is incapable of good, a principle I am sometimes inclined to agree with after eating the horrible food at the "Jansen's Dining" eating facility at Cornell University.