It has been said that Avicenna wrote the argument while imprisoned in the castle of Fardajan, in the Iranian province of Hamadan. He reached the conclusion that the soul is immaterial and substantial. He also claimed that humans can not be denied their consciousness and awareness. According to Avicenna the floating man could attain the concept of being without any sense experience.

The floating man argument is concerned with one who falls freely in the air. This subject knows himself, but not through any sense perception data. Floating or suspending refers to a state in which the subject thinks on the basis of his own reflection without any assistance from sense perception or any material body. This mind flutters over the abyss of eternity.

According to Avicenna, we can not deny the consciousness of the self. His argument is as follows:

One of us must suppose that he was just created at a stroke, fully developed and perfectly formed but with his vision shrouded from perceiving all external objects – created floating in the air or in the space, not buffeted by any perceptible current of the air that supports him, his limbs separated and kept out of contact with one another, so that they do not feel each other. Then let the subject consider whether he would affirm the existence of his self. There is no doubt that he would affirm his own existence, although not affirming the reality of any of his limbs or inner organs, his bowels, or heart or brain or any external thing. Indeed he would affirm the existence of this self of his while not affirming that it had any length, breadth or depth. And if it were possible for him in such a state to imagine a hand or any other organ, he would not imagine it to be a part of himself or a condition of his existence.

—?Avicenna, "DE Anima , the book of Healing' Na", Avicenna, L E Goodman

This argument relies on an introspective thought experiment. We have to suppose a man who accidentally comes into existence fully developed and formed, but he does not have any relation with sensory experience of the world or of his own body. There is no physical contact with the external world at all. According to Avicenna, this subject is, nonetheless, necessarily conscious of himself. In other words, such a being possesses the awareness of his own existence. He thereby believes that the soul has an unmediated and reflexive knowledge of its own existence. Thus appealing to self-consciousness, Avicenna tries to prove the existence of soul, or Nafs. This argument is not supported by the concept of substance in metaphysics. This experiential field shows that the self is not consequently a substance and thereby there is no subjectivity. On the other hand some scholars like Wisnovsky believe that the flying man argument proved the substantiality of the soul.^{[10][full citation needed]} Ibn Sina believes that innate awareness is completely independent of sensory experience.^{[11][full citation needed]}

Before the French philosopher Descartes (1596–1650) pointed out the existence of the conscious self as a turning point in epistemology, using the phrase "Cogito ergo sum," the 11th century Tajik-Persian philosopher Avicenna had referred to the existence of consciousness in the flying man argument. Thus, long before Descartes, Avicenna had established an argument for the existence of knowledge by presence without any need for the existence of the body.^[12]

There are two stances on the relationship between the arguments of Avicenna and Descartes. Some scholars believe that there are apparent similarities between the floating man and Descartes' cogito. Others consider these similarities trivial and superficial.^{[13][full citation needed]} Both Avicenna and Descartes believed that the soul and self are something other than sense data. Also, Avicenna believed that there is no relation logically between the self and the body. In other words, there is no logical dependency between them.^[14]

Adamson thinks that the weakness in the argument is that, even if the flying man would be self-aware, the thought experiment does not prove that the soul is something distinct from the body.^[15] One could argue that the self-awareness is seated in the brain. In this case, in being self-aware the flying man is only aware because of his brain that is doing the experiencing, not because of a distinct soul. He just doesn't realize that the self-awareness is a property of his nervous system.^[15]

• Avicenna
• Knowledge by presence
• Islamic philosophy