Mundaka Upanishad, Chapter One: Section I, Verses 1 and 2: “Brahma first of the Gods was born, the creator of all, the world’s protector; he to Atharvan, his eldest son, declared the God-knowledge in which all sciences have their foundation. The God-knowledge by Brahma declared to Atharvan, Atharvan of old declared to Angir; he to Satyavaha the Bharadwaja told it, the Bharadwaja to Angiras, both the higher and the lower knowledge.”
The creation of the universe is described in the Rig Veda, X.129.1-5: “Then existence was not nor non-existence, the mid-world was not nor the Ether nor what is beyond. … That One lived without breath by his self-law, there was nothing else nor aught beyond it. In the beginning Darkness was hidden by darkness, all this was an ocean of inconscience. When universal being was concealed by fragmentation, then by the greatness of its energy That One was born. That moved at first as desire within, which was the primal seed of mind. … There were casters of the seed, there were Greatnesses; there was self-law below, there was Will above.” (translated by Sri Aurobindo in The Life Divine, pg.240)
Within the context of this Vedic cosmology, we place Brahma, “the first of the Gods” who then created the rest of the universal manifestation. The Gods, as described by Sri Aurobindo, are the cosmic powers of existence that manifest all things in the universe.
The Upanishad describes both a “higher and a lower knowledge”. The higher knowledge is the knowledge of Brahman. The lower knowledge is the knowledge of the powers, forms and forces that exist in the created universe. God-knowledge encompasses “all sciences”, embracing both the knowledge that can only be known by identity, and the knowledge which can be organized and transmitted through the reasoning intellect of the mind, as well as the knowledge which is involved in Matter and Life and is known as “instinct”. Instinct is the term we use for an inherent knowledge of a life-way of a being who does not have an organized mental system for communication, and education of the next generation to that life way. For instance, monarch butterflies undertake a multi-thousand mile journey from Mexico to Canada and back, encompassing 4 successive generations of butterflies, and yet they reach the right destination and return to the right destination despite the 4th generation never having known through education what the 1st generation knew. This is a simple example of involved knowledge. Another is the encoded information in a seed that becomes a specific type of tree. Simply reviewing all the organized facts and deducing principles, the mental processing that takes place in the world, cannot explain these things. It takes the knowledge of Brahman and an understanding of the principles and significance of the creation to truly comprehend these things.
The knowledge is communicated from the Creator of all, Brahman, directly to his eldest son, who is called elsewhere “manas putra” or “mind-born” son. The knowledge is communicated through a lineage. The names recited are in some cases included in the lists of the “sapta rishis’, the 7 great sages who have both the higher and lower knowledge and whose role it is to intermediate this knowledge to humanity. This is not something that can be written down in a book. The Upanishad itself is meant to provide notes along the way, not a comprehensive step by step analysis. The role of the Guru is thereby set forth, and the God-realised soul is able to touch other souls and thereby communicate the knowledge.
Sri Aurobindo, The Upanishads, Mundaka Upanishad, pp. 193-210