For as long as it can remember, the human race has been asking itself whether it is the master of its own destiny or, instead, whether human destiny is dictated by stars, deities, or genes. Today, few question anymore that the brain has a great deal to do with destiny. Modern neuroscience, however, is in the main deterministic and reductionistic, averse to the idea that there is a place in our brain for free will or any other sort of “counter-causal” entity.

Yet, thanks to recent advances in cognitive neuroscience, which is the neuroscience of knowledge, that panorama is about to change or is changing already. When it comes to the cognition of human action, both radical determinism and radical reductionism are no longer the beacons to guide our discourse. That does not mean that free will can already claim a sovereign place in the brain in the form of a distinct entity or set of neural mechanisms. What it does mean is that our scientific understanding of the human brain is opening up to accommodate liberty; that is, to accommodate our capacity to act as free causal agents, albeit within physical and ethical constraints.

The subject of this chapter is the power of speech to protect and enhance our freedom. Thus the focus here is on verbal expression as the brain’s tool and guarantor of freedom in human society. Speech is the most human of all human abilities, the ultimate achievement of the evolution of organisms in their long journeys of adaptation to their environment. By speech we demarcate our existence among our fellow humans. By speech in the future tense we expand that existence forwards in time and assert our liberty to do it.

Speech is the verbal expression of language, which is a core cognitive function in the neurobiological patrimony of our species. Language is so central to cognition that some have equated the two. “Logos” (Greek, word) is at the essence not only of language but also of logical thinking, the two most distinctive constituents of the human mind. Their cognitive primacy, however, does not negate their primal origin. There are means of communication in lower species that qualify as precursors of language, though they are far from language itself. The cerebral evolution of language is accompanied by the evolution of the anatomical apparatus for talking.

It is virtually impossible to discuss the cerebral foundation of liberty without dealing with the evolution of the brain. The reason is simple: The capacity of mammalian organisms to modify their environment by choice and to adapt to it by chosen means has grown enormously with the evolutionary growth of certain parts of their brain, the cerebral cortex in particular. Most relevant to our present discourse is the cortex of the frontal lobes. It is indeed a remarkable fact with a touch of cosmic irony that the science of evolutionary neurobiology, which can only “postdict” but not predict, has unveiled in the prefrontal cortex of man the seed of his future, the capacity to predict and to turn prediction into action that will impact on that future and on that of human society.

The prefrontal cortex is the vanguard of evolution in the nervous system. Yet it is one of the latest cerebral structures to develop, in evolution as in the individual brain (Preuss et al., 2004; Rilling, 2006; Schoenemann et al., 2005; Sowell et al., 2003). Language and prediction, the two most distinctively human functions that the prefrontal cortex supports, are anchored in the history of the species, as is the structure of the prefrontal cortex itself. In the human brain, the latter is tied to its evolutionary past and to the future it anticipates. Thus, while the human brain cannot predict evolution, it can predict the consequences of its actions, with them to predict and shape further actions in a continuous cycle, the perception/action (PA) cycle, which functionally links the organism to its environment.

Our liberty, our ability to choose one course of action or another, emerges from the relationship of our cerebral cortex with our environment. As we have seen in previous chapters, any willed act results from the interactions between the perceptual and executive networks of the cortex, which are at the interface of our organism with the environment. In the free pursuit of our goals, that interface is continuously crossed in both directions by the PA cycle. We have also seen that, internalized in our cortex, we carry much of the outside world in a big bundle that includes our history, our culture, our mores, our traditions, our knowledge, and all the rest of our experience, which in the aggregate defines our persona and which Ortega (1961) calls circumstance (“I am myself and my circumstance”) and Dennett (2003) culture.

By now I trust I have succeeded in helping my reader reach the correct conclusion that the argument about the existence or nonexistence of free will, as an absolute all-or-none, is moot and not relevant to neuroscience. Freedom is graded, like most nervous functions, and so is responsibility, which is inextricable from it. We are indeed free, inasmuch as our brain, more specifically our cerebral cortex, has the option to take one action or another. But we are not completely free, inasmuch as its options are limited, and thus inasmuch as the brain has limits, and inasmuch as the society in which we live imposes on us limits of its own.