By BOB MARTIN

Contributing columnist

Steve Pinker is a Johnstone Family Professor of cognitive psychology at Harvard.  In his book titled “The Blank Slate: The Modern Denial of Human Nature” (2002) he says leftists argue that human nature is driven exclusively by culture.

If little Johnny is prone to violence, it is due to his parenting and socialization. This belief grew even as science compiled considerable evidence that genetics makes a substantial contribution to behavior. After all, the purpose of natural selection is to change behavior.

The left labels those who believe biology influences behavior racists, misogynists or homophobic. The fear of such labels normally shuts down any consideration of the role biology plays in human nature.

Why is the left unwilling to let the science speak? The short answer is the relationship between race and genetics is dangerous knowledge. It can easily be misused by those who wish harm to minorities. On the other hand, all academic disciplines sign on to pursue the truth, not hide the truth; particularly when the truth can lead to new science that enhances all our lives.

The blank slate refers to the “tabula rasa,” which holds we are born with minds untouched by experience and devoid of biological programing. If true, behavior is driven exclusively by what we learn from parenting and culture. Hence, social engineering can create a better society … or, it might create a monstrous civilization. On the other hand, if the slate is hardwired by our DNA, we are impervious to social engineering.

Per Pinker, modern activists maintain three dogmas:  The blank slate, the noble savage and the ghost in the machine. The mind at birth exists, but has no innate characteristics; in a natural state people are good, but are corrupted by society; and we all have a soul that makes choices independently from our biology, respectively. At birth, we are plastic, capable of being molded into any gender role or sexual preference the engineer prefers.

The scientific position is complex interactions between socialization and genetic heritage drives behavior. For scientists, neither culture nor DNA are destiny. This difference between science and modern denial is more important than as simple fodder for retired academics with too much time on their hands.

Identity politics needs the strong form “nurture” hypothesis. If social roles are learned exclusively from culture then culture is a conspiracy by and for the powerful; hence, patriarchy is a conspiracy by men to oppress women rather than the evolutionary product of hundreds of thousands of years of evolution. Men protecting women and children is the result of an evolutionary imperative. Patriarchy is obsolete in Western civilization because life is no longer dangerous, short, or brutal. If we don’t defend Western civilization, however, women must contend with cultures where patriarchy is not obsolete.

If culture is subject to evolution, as are we, current cultures must have some parts that are efficient adaptations for the survival of civilization. Marriage and the family are prime examples of such adaptations. This suggests the need for caution when setting out to dismantle parts of a culture — the action should at least be carefully debated.

All public policy reflects some implicit model of human nature. If the model of human nature is flawed, the policy is flawed. For example, Obamacare is built on a defective human nature model. The mandates to buy insurance and what will be included in each policy assumes everyone will buy the same insurance product.

Eric Holder famously said we are a “nation of cowards” because we are unwilling to have an “honest conversation” about race. He was right, but probably not for the reasons he had in mind. We need to have that conversation; but, it must occur with all the scientific information on the table.

Bob Martin is Emeritus Boles Professor of Economics at Centre College.