In the fifth book of his De aspectibus, the medieval Latin version of Ibn al-Haythamb al-Manir, Alhacen undertakes to determine precisely where a given ray of light will reflect to a given center of sight from a variety of convex and concave mirrors based on circular sections. As applied specifically to convex and concave spherical mirrors, this problem exercised several seventeenth-century thinkers, Christiaan Huygens foremost among them, and in that context it soon became known as Alhazens solution (or solutions) of (...) this problem is deficient in comparison to that of Huygens and later mathematicians. It is my purpose in this paper to show by reconstruction that in fact, far from deficient in any absolute sense, Alhacen’s approach to this problem was remarkably ingenious and elegant in its conceptual simplicity. (shrink)

The author?s approach is based on three premises: 1. that Gajo Petrovic?s Praxis was an outstanding phenomenon in Croatian, Yugoslav and European culture, a challenge of freedom in a repressive society; 2. that there has never been such a thing as "Praxis group", "philosophers of practice" or "Praxis philosophers" with a unified philosophical and socio-theoretical orientation; and 3. that political and ideological attacks on Praxis were part of the repressive system that targeted every instance of cultural and scientific dissent. The (...) political leadership of Tito?s regime, its ideological and propaganda apparatus systematically disseminated allegations, denunciations and accusations against Praxis and Gajo Petrovic. The same style has survived through radical historical changes from the appearance of Praxis until today. The attackers have often been the same persons, with the difference that in earlier times they denounced Praxis and Gajo Petrovic as enemies of "socialism" and the "socialist self-management system", and in the changed political fashion as "servants" of Tito?s authoritarian rule. The fate of Praxis in the former regime has been triumphantly interpreted as a "family quarrel". This paper attempts a sociological analysis of the political destiny of Praxis. The analysis is essentially determined not by old and new political and ideological questionings of Praxis, but by Gajo Petrovic?s fundamental belief that there is no freedom without the human or humanity without freedom.. Osnovu autorovog pristupa cine tri stava: 1. da je Praxis Gaje Petrovica bio izuzetna pojava u hrvatskoj, jugoslovenskoj i evropskoj kulturi, izazov slobode u drustvu represije; 2. da ne postoji tako nesto kao "praxis-grupa", "filozofi prakse" ili "praxis filozofi" koji bi imali jedinstvenu filozofsku ili drustveno-teorijsku orijentaciju; 3. da su politicka i ideoloska osporavanja Praxisa bila deo represivnog sistema kojem je bilo podvrgnuto svako neistomisljenistvo u kulturi i nauci. Politicki vrh Titovog rezima, njegov ideoloski i propagandni aparat sistematski su sirili insinuacije, denuncijacije i optuzbe o Praxisu i Gaji Petrovicu, da bi taj manir u bitno promenjenim istorijskim okolnostima, trajao od pojave Praxisa do danasnjeg dana. Cesto su i akteri napada bile iste osobe, samo sto su nekada osporavali Praxis i Gaju Petrovica kao neprijatelje "socijalizma" i "sistema socijalistickog samoupravljanja", a u promenjenoj politickoj modi kao "sluge" Titove autoritarne vladavine. Sudbinu Praxisa u prethodnom rezimu slavodobitno su tumacili kao "obracun u obitelji". Rad je pokusaj socioloske analize politicke sudbine Praxisa, koju ce bitno odrediti temeljno uverenje Gaje Petrovica da nema slobode bez coveka ni ljudskosti bez slobode, a ne stara i nova politicka i ideoloska osporavanja Praxisa.. (shrink)