This agent could not be perceived by any of the senses

If the world would be produced anew, it must needs have a producer or creator; and if so, why did this creator create the world now and not before? Was it because some motive supervened which it had not before? But there was nothing besides him, the Creator. Was it then owing to some change in his own nature? If so, what has caused this change?…And he perceived that, if he supposed the world to be created in time, and to have had an existence after non-existence, it would necessarily follow therefrom that the world could not come forth into existence by its own power, but required some agent to produce it; but this agent could not be perceived by any of the senses; for if it were an object of the senses, it would be body and if body, part of the world, and would have had its existence anew; so that it would have stood in need of some other cause which should have produced it anew. And if this second creator were also a body, he would depend on a third, and that third upon a fourth, and so on ad infinitum, which, however, would be absurd and irrational.

— from Alive, Son of Awake

Ibn Tufail (c. 1105–1185) was a Spanish Muslim thinker and writer, famous for writing the first philosophical novel, Alive, Son of Awake (also known in the West as Philosophicus Autodidactus). As a physician, he was an early proponent of dissection and autopsy as methods of furthering medical knowledge. Anticipating Daniel Defoe’s Robinson Crusoe by 500 years, Alive, Son of Awake tells the story of a self-taught child raised by a gazelle while living alone on a desert island whereby he discovers the ultimate truth through reasoned inquiry. The book had tremendous influence on the Enlightenment thinkers of the 18th Century.