Education
Leonard Lessius studied theology in Rome under Suarez and Robert Bellarmine.
Leonard Lessius studied theology in Rome under Suarez and Robert Bellarmine.
Lessius is now best known for his treatise De iustitia et iure (On justice and law), of 1605 that went through more than 20 editions in the 17th century alone. It is probably the first in-depth moral theological approach to economic and financial questions. Lessius went to Antwerp, then a world business centre in rapid expansion, to study how banking and commerce were functioning. His experience gave weight to his ethical solutions to moral cases dealing with business and finance. He has been praised by modern historians of economics for the subtlety of its understanding of business matters involving interest. For example Lessius clearly states the dependence of the price of an insurance contract on the risk of the event insured against. Among other things he gave guidelines for a new ‘just price’ approach, accepting the fact that what was proposed by Thomas Aquinas was no longer workable in the 16th century.
His work On the Providence of the Deity, and the Immortality of the Soul, Against Atheists and Politicians, containing design arguments for the existence of God, was translated into English in 1631 under the title Rawleigh his Ghost.
From 1610 on, and already in poor health, he turned towards writing ascetical and theological books that had also much success.