From Notes Of Class Talks And Lectures of Volume 6 of The Complete Works of Swami Vivekananda

Dualism recognises God and nature to be eternally separate: the universe and nature eternally dependent upon God.

The extreme monists make no such distinction. In the last analysis, they claim, all is God: the universe becomes lost in God; God is the eternal life of the universe.

With them infinite and finite are mere terms. The universe, nature, etc. exist by virtue of differentiation. Nature is itself differentiation.

Such questions as, “Why did God create the universe?” “Why did the All – perfect create the imperfect?” etc., can never be answered, because such questions are logical absurdities. Reason exists in nature; beyond nature it has no existence. God is omnipotent, hence to ask why He did so and so is to limit Him; for it implies that there is a purpose in His creating the universe. If He has a purpose, it must be a means to an end, and this would mean that He could not have the end without the means. The questions, why and wherefore, can only be asked of something which depends upon something else.