Our minds -- our thoughts, ideas, and actions and everything that we see, know, or can know -- is somehow related to the incredibly complex network of interconnected neurons in the brain and their electrochemical firings. A reductionist view will tell you that the brain can be reduced to individual neurons. Neurons reduce to biochemistry, and biochemistry reduces to the laws of physics. However, even once we have reduced everything to the interactions between the four basic physical forces: nuclear strong, nuclear weak, electromagnetic, and gravity, this does not satisfactorily describe the workings of a living neuron, and even less so, the mind.
It is the nature of complex systems that the details at a lower level do not necessary explain the whole at a higher level. Conversely, it is possible to satisfactorily understand a phenomenon without understanding all the details of its working. We can use Newton’s laws of motion to describe the motions of the human body at a macroscale level, even if they are technically inaccurate approximations, and we can discuss the actions of enzymes without being able to solve Schrodinger’s equations.
By recognizing the hierarchical organization of complex systems like the brain, we can approach each level with the right tools and the right level of abstraction. The next section will present a hierarchical model of the brain, which extends from the most atomic level -- the cellular level, to the basic functional level -- the minicolumn, to the widest level -- the overall organization of the cerebral cortex in terms of structure, learning, and function. We will see how the properties of each hierarchical level affect the levels above and below.