The Isha Upanishad is not philosophy, but a detailed and practical guide to achieving a transformation of consciousness. It starts with an explanation of the divine standpoint, the truth of existence. The ego-centric viewpoint is an illusion, founded on an exclusive concentration on a particular individualisation of what is in reality a universal consciousness that is at all times One while expressing itself as Many. From this new viewpoint, human motives and action are taken up. The shift in standpoint impacts the way we respond to everything. All the oppositions that have vexed our minds are resolved when they can be seen as complementary aspects of one existence. The Upanishad counsels us to integrate and include, rather than separate and exclude. Once it works through these points, it provides practical guidance on how to undertake the change of consciousness and action that is indicated.
Sri Aurobindo notes: “Phenomenal nature is a movement of the conscious Lord. The object of the movement is to create forms of His consciousness in motion in which He as the one soul in many bodies can take up his habitation and enjoy the multiplicity and the movement with all their relations. Real integral enjoyment of all this movement and multiplicity in its truth and in its infinity depends upon an absolute renunciation; but the renunciation intended is an absolute renunciation of the principle of desire founded on the principle of egoism and not a renunciation of world-existence. … The enjoyment of the infinite delight of existence free from ego, founded on oneness of all in the Lord, is what is meant by the enjoyment of Immortality. Actions are not inconsistent with the soul’s freedom. Man is not bound by works, but only seems to be bound. He has to recover the consciousness of his inalienable freedom by recovering the consciousness of unity in the Lord, unity in himself, unity with all existence. This done, life and works can and should be accepted in their fullness; for the manifestation of the Lord in life and works is the law of our being and the object of our world-existence.”
“We have to be consciously, in all our relations with this world, what we really are, — this one self becoming everything that we observe. All the movement, all energies, all forms, all happenings we must see as those of our one and real self in many existences, as the play of the Will and Knowledge and Delight of the Lord in His world-existence. We shall then be delivered from egoism and desire and the sense of separate existence and therefore from all grief and delusion and shrinking … The knowledge of the One and the knowledge of the Many are a result of the movement of the one consciousness, which sees all things as One in their truth-Idea but differentiates them in their mentality and formal becoming. … The opposition between works and knowledge exists as long as works and knowledge are only of the egoistic mental character. Mental knowledge is not true knowledge; true knowledge is that which is based on the true sight, the sight of the Seer…. when we have the sight and live in the Truth-Consciousness, our will becomes the spontaneous law of the truth in us and, knowing all its acts and their sense and objective, leads straight to the human goal, which was always the enjoyment of the Ananda, the Lord’s delight in self-being, the state of Immortality. In our acts also we become one with all beings and our life grows into a representation of oneness, truth and divine joy and no longer proceeds on the crooked path of egoism full of division, error and stumbling.”
Sri Aurobindo, The Upanishads, Isha Upanishad and analysis, pp. 90-97