Re: Avicenna's Doctrine of Cerebral Function
> On Thu, 18 Jan 2001, Gerald S. Wasserman wrote: > > Been a long time since I read it but it is possible you will find > > information relevant to your query in David C. Lindberg's Theories Of > > Vision From Al-Kindi to Kepler, 1976, U. Chicago Press. > Dr Gert-Jan C. Lokhorst replied: [snip] > All in all, I have the impression that there is little reason > to suppose that Avicenna thought that spatial relationships in > the outside world are represented by similar spatial > relationships within the cerebral ventricles. Avicenna did not > think of retinal images, central retinotopic maps or anything > of the sort. Retinal images are beside the point here. Ibn-Sina (known to medieval Europeans as Avicenna) held that an image is formed in the eye (as the quotations in Lindberg's book make clear). He believed such images are formed on the front surface of the crystalline body (which we now call a lens). I'm not sure whether Ibn-Sina discussed the transmission of such images into the brain. His near contemporary, Ibn al-Haytham (known as Alhazen), certainly did. Ibn al-Haytham held that a cross-section of the visual pyramid is transmitted into the brain. The geometry of the visual pyramid (and its cross-section) remained virtually unchanged after the discovery of the retinal image. (There is an article on this topic in the 1979 volume of _Isis_.) I can't recall whether Ibn al-Haytham discussed the storage of such images in the brain or not. His major work in optics has been translated into English by A. I. Sabra. Gary Hatfield UPenn