Dear Dr. Glasersfeld:
Recently I read your article "Homage to Jean Piaget
(1896-1980)", which I found on your web page. In the article you mentioned that the study of "mind, reason
and understanding has been the unwavering focus of philosophy since Descartes." I would like to orient your
attention to a philosopher called Abu Hamid Al Gazali (1058-1128). Al Gazali portrayed, (after a long period of
doubting and refuting everything that did not comply to reason's reign), the inability of reason to comprehend the
absolute and the infinite. To him reason could not transcend the finite and was limited to the observation of the
relative. At Al Gazali's time, Muslim philosophers held that the universe was finite in space, but infinite in time.
Al Gazali argued that an infinite time was related to an infinite space. He was able to create a balance between
religion and reason and identified their spheres as being the infinite and the finite, respectively. Several of al
Gazali's arguments were adopted by St. Thomas Aquinas. Many of Al Gazali's ideas, especially those in his book"Deliverance
from Error" were heard 500 hundred years later from Descartes.
With all respect,
University of New Orleans
ANSWER FROM ERNST VON GLASERSFELD
Dear Mr. Taha-Thomure,
Thank you for your remarks about Al Gazali. I would be very interested in his
book "Deliverance from Error" and would be grateful for bibliographic details of translations into English,
German or Italian. The separation of rational and mystical knowledge is very important in the constructivist way of
thinking and it would be very nice to have details of an Arabic representative. I have traced it back to the
theologians of the Byzantine school in the 3rd century which was rediscovered by the Irish mystic/philosopher John
Scottus Eriugena in the 9th century and strongly recommended by Cardinal Bellarmino at the time of the trial of
Galileo. I am not a historian and have no idea whether Aquinas took the idea from Eriugina (whom he certainly read)
or from Al Gazali - or from both.
I follow Kant in the belief that time and space are imposed on experience by
the human mind and that the "reality" beyond our experiential interface is therefore not conceivable to us,
because, as Berkeley so clearly saw, we have no idea of what "existence" might mean without a
Although I am rather ignorant of Buddhist philosophy, I believe that at least
certain Tibetan versions of it have also made a strict separation between the rational and mystical intuitions,
probably since about 600 B.C. As I said, I would be grateful for a reference to Al Gazali.
With best wishes,
Ernst von Glasersfeld