Free Will and the Triune Brain

In "The Republic," written in 370 BC by the Greek philosopher Plato, a new understanding of the human soul was introduced: the Tripartite Theory. The soul now has three parts: "reason, "spirit," and "appetite", corresponding to brain, heart and belly. Modern-day neuroscience and psychology has found that evolution has fundamentaly organised the human brain, so that it consists to three brains in one: the reptilian complex, the limbic system, and the neo-cortex.

The reptilian complex, existing since 400 million years, controls normal involuntary behaviour that the conscious mind does not, such as the cardiac and respiratory functions. The reptilian complex is found in all vertebrates and is the most primitive structure of a brain during the species evolution. It is pre-programmed and has only a short-term memory.

The limbic system, existing since 65 million years, is similar to the brain of the more primitive mammals and is the source of emotions and behaviour. It operates by influencing the autonomic nervous system and acts as a filter to select information to record in his long-term memory.

This limbic filter excites the cortex depending on the filter itself linked to the emotional feelings. It is highly interconnected with the nucleus accumbens, the pleasure center of the brain, which plays a role in sexual arousal and the heavy derived from certain recreational drugs. It is involved in reward, placebo effect, pleasure, laugher, addiction, fear and aggression.

The neo-cortex, existing more recently since 3.6 million years, resembles the brain of more recent mammals in that it controls more highly evolved mental capacity such as reason and speech. It is involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning, and in humans, mind, language, conscious thought and anticipation of acts.

It is important to know the structure of the brain, because this can explain some anomalies in the way of reasoning and free volition of the conscious mind. For example, the decision making to stop any addiction to products, like alcohol, and drugs, like medications, mainly depends on the limbic system, and thus is not controlled by way of rational reasoning of the neo-cortex.

The conscious will, when we become aware of it, is the same will as the unconscious will. The fact that this unconscious will becomes a conscious will, is just the translation of the unconscious script to a conscious script embedded in the brain. Indeed, the orbitofrontal cortex is the conscious rational complement of the unconsciously working limbic system. The orbitofrontal cortex unconsciously receives the emotional limbic stimulations, but consciously makes them rational for the real world conditions by way of reasoning.

The human languages are a means of communication between individuals, but also a means of self-communication permitting the self-reference, and consciousness. The emergence of languages was due to the necessity to have a means to memorise space-time events. So to refer to past, present, and future events, the brain needs a repository medium given by a memory. For manipulating the content of this memory, a language is necessary. The ability to recall past events and anticipate the future is crucial for the development of intelligence, and is only possible with a language.

However, this does not mean that we do not have free will. After all, we can evaluate and reflect on our decisions afterwards and decide to take a different course of action when a similar situation arises. Our ability to plan ahead means that we're not condemned to our fate but can exercise a certain amount of control over our own situation.

An interesting question deals with the difference between the human natural languages and computer artificial languages. In computers, all programs are given by an ordered succession of instructions and commands, written in artificial languages, created by man. The artificial languages are similar to the natural languages except that there is no ambiguity in their meaning.

In machine code, any instruction or command, in artificial languages, gives rise to a specific action on the machine (the computer microprocessor), which represents its meaning. All the cells in the body, and in the neurons in the brain, are also programmed by the genetic code, DNA, in a low-level language with four elementary signs. However, natural systems do not deal with real numbers, with an infinite number of decimals, as computers do.

Based on the development of the human embryo, the brain is completely integrated in the ectoderm, and cannot work alone. The classical paradigm of the neural brain as the seat of human natural intelligence is too restrictive. The brain is only a part of the human body, and a brain without a body cannot work. In the same way, the human being is only a part of its environment, and cannot exist without it. The development of a human being is only possible if there is a set of other human beings, the whole of which we call humanity.

Source: Daniel M. Dubois, 2010

Brain