Witelo (also Erazmus Ciolek Witelo; Witelon; Vitellio; Vitello; Vitello Thuringopolonis; Vitulon; Erazm Ciołek; born ca. 1230, probably in Legnica in Lower Silesia; died after 1280, before 1314) was a friar, theologian and scientist: a physicist, natural philosopher, mathematician. He is an important figure in the history of philosophy in Poland. On the Moon there is a crater, Vitello, named after him.
Witelo's mother was from a Polish knightly house, while his father was a German settler from Thuringia. He called himself, in Latin, "Thuringorum et Polonorum filius" — "a son of Thuringians and Poles." He studied at Padua University about 1260, then went on to Viterbo. He became friends with William of Moerbeke, the translator of Aristotle. Witelo's major surviving work on optics, Perspectiva, completed in about 1270–78, was dedicated to William. In 1284 he described reflection and refraction of light.
Witelo's Perspectiva was largely based on the work of the Persian polymath Alhazen (Ibn al-Haytham; d. ca. 1041) and in turn powerfully influenced later scientists, in particular Johannes Kepler. Witelo's treatise in optics was closely linked to the Latin version of Ibn al-Haytham's Arabic opus: Kitab al-manazir (The Book of Optics; De aspectibus or Perspectivae), and both were printed in the Friedrich Risner edition Opticae Thesaurus (Basel, 1572).
Witelo's Perspectiva, which rested on Ibn al-Haytham's research in optics, influenced also the Renaissance theories of perspective. Lorenzo Ghiberti's Commentario terzo (Third Commentary) was based on an Italian translation of Witelo's Latin tract: Perspectiva.
Perspectiva also includes Platonic metaphysical discussions. Witelo argues that there are intellectual and corporeal bodies, connected by causality (corresponding to the Idealist doctrine of the universal and the actual), emanating from God in the form of Divine Light. Light itself is, for Witelo, the first of all sensible entities, and his views on light are similar to those held by Roger Bacon, though he is closer in this to Alhazen's legacy.
In Perspectiva, Witelo refers to other works that he had written. Most of these do not survive, but De Natura Daemonum and De Primaria Causa Paenitentiae have been recovered.
- History of philosophy in Poland
- List of Poles
- List of Roman Catholic scientist-clerics
- Clemens Baeumker, "Witelo: Ein Philosoph und Naturforscher des dreizehnten Jahrhunderts," Beiträge zur Geschichte der Philosophie des Mittelalters, part 3, no. 2, Münster, Aschendorff, 1908.
- Władysław Tatarkiewicz, Historia filozofii (History of Philosophy), 3 vols., Warsaw, Państwowe Wydawnictwo Naukowe, 1978.
- Jerzy Burchardt, "The Discovery of the Rainbow in Crystal by Witelo"
- "Witelonis Perspectivae liber primus", Wrocław 1977
- Online Galleries, History of Science Collections, University of Oklahoma Libraries High resolution images of works by and/or portraits of Witelo in .jpg and .tiff format.