Acharya Prashant explains the evolutionary journey of the human brain, starting from inert material and chemicals that eventually formed proteins and protoplasm. He describes how these substances gradually developed the ability to respond to their environment, leading to the birth of single-celled organisms like amoeba and paramecium. Over millions of years, through constant interaction with and assimilation of the environment, these organisms evolved into more complex creatures, eventually resulting in the human being. He emphasizes that the brain is the culmination of this long process of evolution and is essentially composed of experiences gathered over millions of years. He further asserts that the brain is fundamentally defined by time and space. He explains that time and space are not external entities but are properties of the human brain itself. The brain is a product of time and space and is only capable of perceiving time and space. He defines time as change occurring within space, noting that these two are inseparably linked. Ultimately, he concludes that every cell of the brain is a product of the past, and the brain is nothing but the accumulation of that past through the fabric of space-time.