Unlike Mesmer, who claimed that hypnosis was mediated by "animal magnetism", Faria understood that it worked purely by the power of suggestion.

Faria was one of the first to depart from the theory of the "magnetic fluid", to place in relief the importance of suggestion, and to demonstrate the existence of "autosuggestion"; he also established that what he termed nervous sleep belongs to the natural order.

Later, Ambroise-Auguste Liébeault (1864–1904), the founder of the Nancy School, and Émile Coué (1857–1926), father of applied conditioning, developed the theory of suggestion and autosuggestion and began using them as therapeutic tools.

José Custódio de Faria was born in Candolim, Bardes in the erstwhile territory of Portuguese Goa, on 31 May 1756.

After a year they managed to convince the King of Portugal, Joseph I, to send them to Rome for Faria Sr. to earn a doctorate in theology, and the son to pursue his studies for the priesthood.

Apparently the pope was sufficiently impressed to invite José Custódio to preach a sermon in the Sistine Chapel, which he himself attended.

Faria Jr., from then on, often wondered how a mere phrase from his father could alter his state of mind so radically as to wipe off his stage fright in a second.

He was also a friend of Armand-Marie-Jacques de Chastenet, Marques of Puységur (a disciple of Franz Anton Mesmer), to whom he dedicated his book Causas do Sono Lúcido ("On the Causes of Lucid Sleep").

There is a bronze statue of Faria trying to hypnotise a woman in central Panjim, Goa, India (next to the former Government Secretariat or Idalcão palace).

[5] Portugal commemorated the 250th anniversary of the Faria's in May 2006 by releasing a postcard (featuring his statue in Panjim, Indi[citation needed] street in the Areeiro zone of Lisbon is also named in his honour.

[8] Jaime Valfredo Rangel presented a paper in tribute of his 200th birth anniversary to the Governor of Portuguese India, Paulo Bernard Guedes.

Kator Re Bhaji, is a play was written and directed by Isabel de Santa Rita Vas and performed by the Mustard Seed Art Company, an Indian theatre troupe from Goa, which celebrated the 250th anniversary of Faria's birth.