There is an objection that if Satan exists, then why
men are unable to see him? This is an invalid objection.
Human eyes cannot see rare things. They can only visualize
things that have volume. Can we see the air that is
absolutely rare. Can we see the waves of the wind, although
we feel them blowing. The human eye is made of soil
and it can only see the voluminous things. Therefore
the Holy Quran says:
Innahu yarakum huwa wa qabeelau min haisu laa taraunahum
He and his troops look at you from such a place
where you cannot see them.
Yes! At certain times the satans can make themselves
visible to people. Many prophets such as Hazrat Nooh
(a.s.), Hazrat Yahya (a.s.), Hazrat Mohammed (a.s) and
many men of high piety have seen Satan and even now
some pious persons must be there who have this experience.