When viewed without the twin distortions of love and hate, like and dislike, all forms, all effects, all causes are experienced as Brahman only.
But when the vision is affected by love and hate, each form, each effect and cause appears different from the rest.
When one mediates, the mind is calm and feelings are balanced, only in these conditions can one experience the many as One.
An agitated mind can never have a single vision. It runs along contrary lines, so it experiences the world, nature and the Cosmos as separate from Brahman. Such vision creates division.
A calm vision reveals unity. As the vision, so the impression, and the view of the world.