The article substantiates Abu Ali ibn Sina's philosophical views on existence and knowledge based on scientific sources. Abu Ali Abu Ali ibn Sina's ontological views were mainly influenced by Neoplatonism. The main categories of the doctrine of existence are matter, motion, space, time, substance. The article mentioned that Abu Ali ibn Sina put forward the opinion that nature is eternal and eternal, its laws do not change by themselves, man is able to understand them, the soul is determined by the activity of the body, and its individual immortality is impossible.