# Can we determine the exact time of declination of science in Islamic Period?

According to the 'Classical Narrative', al-Ghazali and ash'arian anti-philosophy attack ended what is commonly called golden age of science. But the discovery of non-Ptolemaic Models and their important role in development of the Copernican models of universe raised serious doubt concerning the validity of this claim. It showed that not only astronomical traditions in Islamic period did not finish in the thirteenth century, but also they contributed immensely to the intellectual heritage of that period. Technical innovations and complex mathematical models used by astronomers at this time made this period golden age of science.

As recently argued by Saliba and some other historians, contrary to what the 'Classical Narrative' states varieties of methods and techniques used by Islamic astronomers during this period demonstrate high level of creativity and innovations. This paper consists of two parts. In the first part, I will consider these models in details and will explain complicated and intelligent mathematical methods used in them.Using Kuhn's terminology, I will describe this period as a crisis time in which different solutions to anomalies have been offered by Islamic astronomers to rescue the original paradigm. These models are originated and developed from a philosophical and theoretical tension within the Ptolemaic-Aristotelian framework. On the other hand, some known points connect these models with the Copernicus's heliocentric models.

In the second part, I will raise the following questions:

1.These models, except the Ibn al-Shatir's sun model, were not developed to correct any quantified observational problems which is the original goal of astronomical activities. I suspect there are two criteria by which we can identify a golden period. These criteria are plentitudes of new models in Hay'a books, and mathematical and observational considerations in Zijes. The main question is according to which criterion the 'Golden Age' should be chosen.

2.Can progress in a special aspect of astronomy mean a progress in other abstract aspects of astronomy and also in other sciences?

Having raised the above questions, I will express my reservations regarding whether it is appropriate to call that period golden age of science.

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