Consciousness is the very form of existence,though one would find it difficult to understand because of the intoxication of experience of duality,which is present in the form of universe.

People who argue that soul does not exist are not aware of the fact that their own existence is dependent on the soul, which is in the form of consciousness. 

One should not conclude something as ultimate  truth or Brahman  because some great thinker said so or some philosophy says so. Without consciousness the mind, which is in the form of universe ceases to exist. Man ceases to exist without the universe. 

 The soul is in the form of formless consciousness. Formless consciousness is the formless substance and witness of the mind or universe, which appears as waking or dream.

 That is why Buddha said:- 

 

Do not believe a spiritual teaching just because:-

1. it is repeatedly recited,
2. it is written in a scripture,
3. it was handed from guru to disciple,
4. everyone around you believes it,
5. it has supernatural qualities,
6. it fits my beliefs anyway,
7. it sounds rational to me,
8. it is taught by a respectable person,
9. it was said to be the truth by the teacher,
10. one must defend it or fight for it.
However, only when it agrees with your experience and reason, and when it is conducive to the good and gain of oneself and all others, then one should accept the teachings, and live up to them."
....Buddha.

Seeker of truth has to indulge in deeper self-search  by discriminating between the dual (waking or dream) and non-dual (deep sleep) experiences and understand and assimilate this existence of formless witness( consciousness), which is beyond the form time and space. Consciousness is the very form of existence,though one would find it difficult to understand because of the intoxication of experience of duality,which is present in the form of universe. 

This formless non-dual consciousness, which is beyond the mind and it, is never subject to any change by any cause, but the waking is subject to change as deep sleep or dream, and when this is realized than one becomes aware of the fact that, the subject and object are one in essence. 

The difference between mind (universe) and soul (consciousness) is only when one considers the waking entity as self. From the ultimate standpoint there is no second thing exist other than consciousness, because the formless substance and witness of the mind or universe is consciousness.  The mind and soul are one in essence.