claims had not been discovered. First, because of its consciousness, the human soul is capable of knowing independent of the body, and thus is capable of existing despite the body's death. Secondly, the human soul does not change even though the body ages or becomes diseased, that is, its essence is not affected by extrinsic factors. Thirdly, it is the desire of all humans to attain happiness, which, alongside the wish to know the future and the consequences of our actions, are the reasons that prompt us to do good, because evil deeds lead to punishment and misfortune. Pereira and Descartes After René Descartes published his Discourse on Method in 1637, the originality of the thoughts was questioned and even said to be an overt plagiarism of Gómez Pereira, as the Spanish philosopher had been studied by many prestigious intellectuals during the 16th and 17th Centuries. The first to suggest the similarities between the two was Pierre Daniel Huet, originally a follower then an opponent of Cartesian philosophy. Descartes himself was forced to defend himself against these accusations, as is evidenced by a letter he wrote in 1641 to his friend Father Marin Mersenne: I have not seen Antoniana Margarita, nor do I have a great need to see it any more than the Theses of Louvain or the book of Hansenius, but I would like to know where to find a copy if you think it necessary. Many scholars of the 17th and 18th Centuries sided with Descartes and despised the work of Pereira, among them Pierre Bayle (although he did recognize the similarity between the two) and the Enclyopedists Diderot and d'Alembert who said: Descartes is the first philosopher who dared to consider animals as mere machines: therefore, Gómez Pereira, who said this some time before him . . . stumbled upon this hypothesis by chance. However, many others have defended the contrary thesis. Even accepting that Descartes may not have read the work of Pereira, they argue that he was influenced indirectly, especially through the work of another Spanish physician and philosopher, Francisco Valles, who read it in French. Among those who accuse Descartes of being a counterfeit are Isaac Cardoso and Voltaire. The basis for this criticism is the striking similarities between the two thinkers on some key points: The empirical method: Descartes' is a priori and deductive, whereas Pereira's is a posteriori and inductive. Souls