Jean-Baptiste-Claude Delisle de Sales or Jean-Baptiste Isoard de Lisle (1741–1816) was a French philosopher, historian, and accused heretic active in the late 18th century. Sales is best known for his publication of the multi-volume opus The Philosophy of Nature: Treatise on Human Moral Nature. The work, among other ideas, challenged the Biblical theory that the earth was created in 4004 BC. Instead, Sales put forth the theory based upon astronomical observations, that the earth was 140,000 years old. Sales' revolutionary ideas caused him to be declared a heretic by the Catholic Church. His publications were subsequently censored and, for the most part, destroyed. As a consequence all of his works are today extremely rare. Sales was also, notably, a close friend of Voltaire who in 1777 visited him in prison, gifting him 500 pounds towards his release. Delisle de Sales is unrelated to the more famous De L'Isle family of cartographers.