Al Ghazali - Medieval Islamic Science
Welcome to Study Guides!

Al Ghazali

Gurgan tomb
Tomb of the scholar Qabus, Gurgan, Iran
(built about 1010 AD)

Al Ghazali was born in northern Persia in 1058 AD, under the rule of the Seljuks. His father, who followed Sufism, died when Al Ghazali was still a boy, and one of his father's friends took him and his brother in. When Al Ghazali was twelve years old, he left home to go to a madrassa in a bigger city, Gurgan.

At the madrassa in Gurgan, Al Ghazali studied the works of earlier philosophers, but he was not happy with the answers he found there. Most of the philosophers he studied followed the Neo-Platonist idea that people's souls were all pieces of one universal divine spirit, and they returned to join that divine spirit when you died. But Al-Ghazali wanted ideas based on scientific experiments and proof, not just ideas.

When Al-Ghazali grew up, he eventually (in 1091 AD) became a professor at the sultan's university in Baghdad. Al-Ghazali wrote a book called "On the Incoherence of the Philosophers" that argued against Aristotle and Plato, and against Ibn Sina. Al-Ghazali rejected the Greek philosophers because they were not Muslims. He argued that what looks to us like the laws of nature is really just proof that Allah is a rational god who acts in consistent and reasonable ways. So gravity and inertia are not laws of nature, but laws of God.

In this way, Al-Ghazali was able to do scientific research while still believing in God. He continued his scientific research, and followed the Greek astronomers Thales and Anaxagoras in correctly understanding how solar eclipses and lunar eclipses work. Al-Ghazali also studied mathematics, arguing that math was a different subject from religion, and that you couldn't learn anything about God by doing math, or about math by studying God. Like Lucretius, Al-Ghazali thought that everything in the world was made of tiny atoms, but he thought the atoms were arranged into patterns by God.

But after only four years, Al-Ghazali decided to quit being a professor, give away all his money, leave his family, and live the life of a poor Sufi religious man. As a Sufi beggar, he travelled to Damascus and Jerusalem, and then to Medina and Mecca, before coming home to Tus. Al-Ghazali died in Tus in 1111 AD, when he was 53 years old.

After Al-Ghazali died, the philosopher Ibn Rushd wrote a defence of Aristotle against Al-Ghazali. But despite this effort, Al-Ghazali's work encouraged many later Islamic astronomers to rely on their own observations instead of philosophy to describe the stars and planets.

Learn by doing: observe an eclipse of the moon
More about Islamic astronomy

Bibliography and further reading about Islamic astronomy:

Thomas Aquinas
Islamic Empire home

LIMITED TIME OFFER FOR TEACHERS: Using this article with your class? Show us your class page where you're using this article, and we'll send you a free subscription so all your students can use Study Guides with no distractions! (Not a teacher? Paid subscriptions are also available for just $16/year!)
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter, or buy her book, Vandals to Visigoths.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Study Guides
  • Publisher:
  • Date Published:
Did you find what you needed? Ask your teacher to link to this page so other people can use it too! Send it in and win a "Great Page!" award!
Sign up for more free articles and special offers in' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more? is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Study Guides, . Web. 30 March, 2017