If the real is misconceived as an object of knowledge, it cannot be known. Empirical objects may be known by outer observation or inner introspection. But the Self cannot divide itself into the knower and the known.
Logical reasoning is incapable of comprehending the living unity of God and man, the absolute and the relative. Logical incapacity is not evidence of actual impossibility. Reality unites what discursive reason is incapable of holding together.
Every atom of life is a witness to the oneness and duality of God and the world. Being can never be objectified or externalized. It is co-inherent and co-existent in man. It is unknowable because we identify existence with objectivity.
Spiritual reality is not revealed in the way in which objects of the natural world or principles of logic are apprehended. Yajnavalkya tell us that the self is its own light when the sun has set, when the moon has set, when the fire is put out – Atmavasya Jyotir Bhavati.
Dr S Radhakrishnan
Source: The Principal Upanishads Introduction, Page 97 – Harper Collins 12th Impression