SANCHES, FRANCISCO (1550/52–1623), philosopher and physician. He was born in either Braga, Portugal, or Tuy, Spain, to a Spanish New Christian family. His father, the prominent physician, Antonio Sanches, was probably from a Castilian Jewish family that included Gabriel *Sanchez, royal treasurer under Queen Isabella. Antonio and his family fled to Bordeaux around 1564, soon after the Inquisition was established in Galicia. Young Francisco apparently studied at the College de Guyenne (Montaigne, his distant cousin, also went there), in Rome and finally received his medical degree from Montpellier in 1574. He was refused a professorship there and moved to Toulouse, where he became professor of philosophy in 1585, and professor of medicine in 1612.
Sanches wrote on philosophical and medical subjects. His earliest writing is a letter to the mathematician, Father Clavius, in 1574–75, offering a skeptical criticism of the Platonic view of mathematics, and the impossibility of gaining any genuine knowledge of reality through mathematics. He wrote his most famous work, Quod nihil sequitur (published in 1581), presenting the best technical exposition of Renaissance philosophical skepticism, and offering the first statement of a limited empirical scientific method as the only positive way of proceeding if genuine knowledge is unattainable. Sanches apparently coined the term "scientific method." He also wrote against astrology and other forms of Renaissance pseudoscience.
Sanches has been considered by some the first modern philosopher. They have seen him as a precursor of Descartes, because of his thoroughgoing skepticism and his method of doubt, and as a precursor of Francis Bacon because of his emphasis on empirical study. However, Sanches' skepticism is more complete than Descartes'. From an analysis of the human epistemological situation, Sanches concluded that nothing could be known about the nature or causes of reality. Human logic and science were unable to determine the real nature of things. Neither the Aristotelian nor the Platonic theories, he contended, were able to give us any genuine means of gaining knowledge. True science would give immediate, intuitive comprehension of the real features of an object. But only God could possess such knowledge. Our limitations, plus the nature of objects themselves, forever prevent us from gaining genuine knowledge. Since nothing can be known, he contended that we should instead do what we can, that is, carry on patient, careful empirical research, and cautiously judge and evaluate the data. This will not lead to knowledge, but to the best information available about the world.
Sanches saw modern science not as a new metaphysical approach to reality, but as a limited empirical way of proceeding when the quest for certainty has been abandoned. Any further information about the world can only be gained by faith. Sanches influenced the later skeptics, as well as some of the major philosophers in the 17th century. His skepticism led to a tradition of mitigated or constructive skepticism that flourished in the 17th century and has been revived in the modern positivistic and pragmatic interpretations of scientific knowledge.
L. Gerkrath, Franz Sanchez (1860); A. Moreira de Sá, Francisco Sanches filósofo e matemático, 2 vols. (1947), includes bibliography; R.H. Popkin, History of Scepticism from Erasmus to Descartes (1964), 38–43; incl. bibl.; J. de Carvalho, in: F. Sanches, Opera Philosophica (1955), vii–liv; M. Menéndez y Pelayo, Ensayos de Crítica Filosófica (1948), 174–201.
[Richard H. Popkin]