The age-old psychological debate about nature vs. nurture has been resolved with the concession that clearly human development is determined by both genetic factors and environmental influences, not to mention free will choices.

Some researchers have focused on the potential influence of free will to a previously unseen extent. This novel research is emerging from an exciting contemporary field in neuroscience called neuroplasticity, which observes how the mind’s power alters the very structure and function of the brain in response to experience. Sharon Begley, the editor of the Wall Street Journal science section, writes: “Like sand on a beach, the brain bears the footprints of the decisions we have made, the skills we have learned, the actions we have taken.” Today, neuroscientists can observe how repeated traumas etch neural pathways to turn grief into depression, how meditating monks can change the level of prefrontal activity by generating feelings of compassion, and how pianists can increase the shape of their motor cortex through sheer imagination.


Medical practitioners have been observing neuroplasticity for many years in patients following a stroke. Often, when one functional cortex experiences damage during ischemia, a neighboring cortex will frequently activate, compensate for the impairment, and take over the function of the damaged region. Thus, after a stroke, some people may lose the ability to speak, but then, with training, their brain reorganization enables them to again achieve the ability to speak. The cutting edge current research provides an additional supplement to our knowledge of how the brain functions and copes with mental and physical injuries.

Before the scientific era, philosophers and theologians dominated the debate of nature vs. nurture, usually as a question of whether humans had free will. The issue was considered a purely philosophical and/or theological argument, given the capabilities of scientific research at the time. In western civilization, from the pagan philosopher Aristotle (pro) through the Reformation era debate between the Protestant Martin Luther (con) and the Catholic theologian Erasmus (pro), the debates utilized rhetoric and current theological thinking as a way of understanding human development and free will.

The nature vs. nurture debate had profound implications for political philosophy and structure as well. Politically, monarchies and their noble supporters have supported the position that nature determines the type of person one is, and can be, over nurture. The noble class argued that they, by hereditary and innate qualities, provided a natural leadership and refinement to society; whereas the inherently ignorant and cruel peasants offered no discernible value to society, and that this was the inevitable order of the world. Not surprisingly, the nobility rarely elevated commoners to noble status. Beginning with the Enlightenment, a counter argument arose favoring the nurture position. John Locke, whose concepts of “Natural Rights” was adopted most famously by Thomas Jefferson in the Declaration of Independence, wrote in his Essay Concerning Human Understanding that humans were born with a mind like a “white paper void of all characters” (sometimes cited with the Latin “tabula rasa,” or “blank slate”), and that “experience” was what filled in one’s character. Thus, Locke rejected the idea that humans had innate qualities, challenging the rationale of the nobility. Over the succeeding centuries, those favoring nurture (usually defined as liberals) have supported issues embracing the possibility of change, such as: protection of civil liberties, rehabilitation of prisoners, broad suffrage, support of labor movements and unions, progressive taxation of the wealthy, and aid to the poor and unemployed, Contrarily, those favoring nature (usually defined as conservatives) seek to preserve the status quo and assume political positions reflecting as much: emphasis on order and stability, restricted suffrage, singular support of business owners at the expense of workers, limited or no taxation, and reduced aid to the poor (if any).

In recent political history, the nature argument can be seen in a litany of issues. Perhaps most infamously the attitude revealed itself when then-presidential candidate Mitt Romney made his “47 percent” comment:

All right, there are 47 percent who are with him [President Barack Obama], who are dependent upon government, who believe that they are victims, who believe the government has a responsibility to care for them, who believe that they are entitled to health care, to food, to housing, to you-name-it. … My job is not to worry about those people. I’ll never convince them they should take personal responsibility and care for their lives.

The suggestion is that it is the poor’s nature to remain pessimistically stuck in hopeless poverty. Collaboration or discussion is of no value since their views (and situations) cannot change.

Presently the nature attitude is evident in the congressional efforts to end unemployment benefits regardless of national statistics showing that there are 3 applicants for every available job. Congressional conservatives argue that continuing unemployment benefits encourages people to be lazy and dependent on social services (as is their nature). Other efforts that reveal assumptions about one’s innate characteristics and attributes can be seen in the extensive state campaigns to restrict voting, for primarily minority and low-income communities, by curtailing early voting, eliminating polling locations to lengthen the already long lines on election day, making voter registration more difficult, and adding identification requirements that many people cannot comply with. This would be classified as a nature-approach, because the aristocracy traditionally has tried to limit suffrage, using property, literacy, and other means to keep those of the lower classes or races from voting. On the nurture side, recent efforts to reduce mandatory and severe sentences for nonviolent crimes indicates a belief that people can reform and that society does not need to imprison people for minor offenses.

Even among scientists, the political implications of the nature vs. nurture debate have had a significant impact on research. One such example of how the debate has been impacted by scientific research and assumptions is evident in comparative genomics. When the genome of the common fruit fly was completed, many predicted that humans would have many times the number of genes, since it was presumed that humans are of a far higher order of creature with infinitely greater mental capabilities. When the human genome was completed, many were shocked and dismayed to learn that about 70 percent of the genes found in the fruit fly were also found in humans. Since learning that fruit flies and humans use the same or similar genes to develop into adults this research has become fertile territory for the nature vs. nature debate. Professor Gerry Rubin, of UC Berkeley and who worked on the genome processing, explains, “They [fruit flies] can become addicted to alcohol, cocaine and other drugs. They have a wake-sleep cycle like humans do. They have complicated rituals of behaviour… in addition to sharing many of the biochemical pathways humans have.” One particularly revealing breakthrough in the comparative genomic study concerned the discovery of BRCA1, or the “breast cancer gene.” Professor Rubin writes, “It turned out that the molecules causing these problems in fruit flies were the same molecules that we know were responsible for causing cancer in humans.” From this comparative genomic study most researchers insist that the causes of cancer lie more with nurture than with nature.

From scientific research much evidence suggests that human development, personality traits, and behavior comes more from nurture than nature. Many philosophers take similar positions and ground their analysis in both physical science and philosophy. Consider the words of philosopher and professor Thomas Nagel, who explains that we are not, in the materialist sense, simply brains on wheels that have evolved:

So if mind is a product of biological revolution—if organisms with mental life are not miraculous anomalies but an integral part of nature—then biology cannot be a purely physical science. The possibility opens up of a pervasive conception of the natural order very different from materialism—one that makes mind central, rather than a side effect of physical law…. Both theism and evolutionary naturalism are attempts to understand ourselves from the outside, using very different resources. Theism offers a vicarious understanding, by assigning it to a transcendent mind whose purposes and understanding of the world we cannot ourselves fully share, but which makes it possible to believe that the world is intelligible, even if not to us. The form of this transcendent understanding is conceived by extrapolation from the natural psychological self-understanding that we have our own intentions (Mind and Cosmos, 15, 23).

Jewish tradition is adamant that humans are free to make choices, yet doesn’t deny that each person has a unique nature. Further Jewish tradition acknowledges that every individual has unique internal psychology and influence from spirituality. Consider a teaching in Avot D’Rabbi Natan (16:62-63):

They said: The bad yetzer is thirteen years older than the good yetzer. From the belly of a person’s mother it grows and comes with him. If he begins to desecrate the Sabbath, nothing in him protests. [If he begins to commit murder, nothing in him protests. If he goes to do an act of transgression, nothing in him protests.] After thirteen years, the good yetzer is born. When he begins to desecrate Sabbaths, it says to him, “You idiot! Look, it says ‘The one who desecrates it will surely die!’” (Exod. 31:14). When he goes to commit murder, it says to him, “You idiot! Look, it says, ‘If a man spills the blood of another man, his blood will be spilled’” (Gen. 9:6). When he goes to do an act of sexual transgression, it says to him, “You idiot! Look, it says, ‘the adulterer and the adulteress will surely die’” (Lev. 20:10).

We are so deeply influenced morally and spiritually in our youth before we are fully capable of making ethical decisions. Those “thirteen years” are invaluable. We should all seek to better understand ourselves and become more cognizant of how our uniquely complex development impacted our character and the people we are today. Me must also remain aware of how G-d has played such an important role in all of our lives and the light he has placed inside of us. We should also approach our successes with humility. As the business saying goes: “Don’t confuse brains with a bull market.” Sometimes people find success because they existed at the right moment. So too, many fail for reasons that are not their own fault, a victim of circumstance or lack of opportunity.

In a dark world we live by what Bertolt Brecht called “Erst kommt das Fressen. Dann kommt die Moral” (grub comes first, and ethics later), an idea sometimes referred to as economic determinism. Economic determinism means that many of us live according to physical needs and our natural instincts but never transcend to higher levels of awareness to live according to our values and principles. Instead, let us learn from science and Jewish teaching. Neuroplasticity teaches us that our minds are shaped by our experiences, so we should seek to create a society that will maximize our ability to keep our minds healthy and capable of making the right choices in life.


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Rabbi Dr. Shmuly Yanklowitz is the President & Dean of the Valley Beit Midrash, the Founder & President of Uri L’Tzedek, the Founder and CEO of The Shamayim V’Aretz Institute, the Founder and President of YATOM, and the author of thirteen books on Jewish ethics. Newsweek named Rav Shmuly one of the top 50 rabbis in America and the Forward named him one of the 50 most influential Jews. 


  1. Jewish teachings don’t seem to conflict with scientific teachings. Scientific revelations don’t seem to conflict with Jewish teachings either. It’s as if you understand that the laws of physics fall under the same tent as other laws given by the Creator. You don’t know how refreshing that is. Understanding is part of your faith, and for that, I second your proposition for us to learn from science and Jewish teaching. Thank you, Rabbi. Now if only I had learned about neuroplasticity and the Jewish faith before I let the former conflicts in my mind turn it into swiss cheese…

  2. Jewish teachings don't seem to conflict with scientific teachings. Scientific revelations don't seem to conflict with Jewish teachings either. It's as if you understand that the laws of physics fall under the same tent as other laws given by the Creator. You don't know how refreshing that is. Understanding is part of your faith, and for that, I second your proposition for us to learn from science and Jewish teaching. Thank you, Rabbi. Now if only I had learned about neuroplasticity and the Jewish faith before I let the former conflicts in my mind turn it into swiss cheese…

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