The Empiric school of medicine (Empirics, Empiricists, or Empirici, Ἐμπειρικοί) was a school of medicine founded in Alexandria the middle of the third century BC. The school was a major influence on ancient Greek and Roman medicine. The school's name is derived from the word (ἐμπειρία "experience") because they professed to derive their knowledge from experiences only, and in doing so set themselves in opposition to the Dogmatic school. Serapion of Alexandria, and Philinus of Cos, are regarded as the founders of this school in the 3rd century BC. Other physicians who belonged to this sect were: Apollonius of Citium, Glaucias, Heraclides, Bacchius, Zeuxis, Menodotus, Theodas, Herodotus of Tarsus, Aeschrion, Sextus Empiricus, and Marcellus Empiricus. The sect survived a long time, as Marcellus lived in the 4th century AD. The doctrines of this school are described by Aulus Cornelius Celsus in the introduction to his De Medicina. The Empiric school said that it was necessary to understand the evident causes of disease, but considered the inquiry after the hidden causes and natural actions to be fruitless, because Nature is incomprehensible. That these things cannot be understood appears from the controversies among philosophers and physicians, and in the way in which the methods of practice differed from place to place, one method being used in Rome, another in Egypt, and another in Gaul. Often too, the causes are evident; as in a wound, and if the evident cause does not suggest a method of curing, then much less so other obscure methods. This being the case, it is much better to seek relief from things certain and tried; that is, from remedies as learned from experience. They said that medicine, in its infancy, was deduced from experiments; for the sick, in a time when there were no physicians, had either taken food in the first days of their illness, or had abstained, and that the illness was more quickly alleviated in one group than the other.