A holistic account of the human brain is provided by the Second Law of Thermodynamics. According to this universal precept, the central nervous system is governed by the quest to consume free energy in the least possible time. The brain is like any other system of nature that has evolved over eons and continues to develop over an individual’s life time. This physical portrayal is singularly appropriate because power-law characteristics as well as oscillatory and at times unpredictable functioning are not exclusive attributes of the brain but are found in other systems throughout nature. The neural network comprises pathways for signal propagation just as other natural systems have pathways for the transmission of energy in various forms. These universalities support the view of the evolution and development of the human brain as a natural thermodynamic process. In a like manner perception, sensation and learning as well as the processes of memory, emotions and consciousness can be regarded as natural expressions of the neural network under the suzerainty of the Second Law. The outcomes of cognitive processes, like other natural processes, are non-deterministic because the interactive effects of flows of energy as signals with differences in energy as their driving forces cannot be separated from each other. This naturalistic framework also provides insight into mental disorders and cognitive defects.