Essentialism is the view that everything has an underlying reality or true nature – a real essence.  For example, essentialism states that there are innate, essential differences between men and women.  That is, we are born with certain traits.   For example, if X is a human being, there is a limit to what one might discover about how X is composed or made.  Given that X is a human being, it could not be true that X is composed of coal, copper, or chromium.  Not being made of coal, copper, or chromium is an essential feature of human nature.  

What essentialism seeks to address is the fluidity and amalgamation in Darwin’s theory of evolution, and the "logical-positivism" philosophy of David Hume and Immanuel Kant (also of Fichte, Hegel and Nietzsche)  who claim that reason is limited, leads to impossible contradictions, and that what we perceive are ‘abstractions’ (i.e., not objective features of the world). The danger in Darwinian and Kantian-like thinking is that absolutes go missing, everything becomes relative, and lines of demarcation fade. In art you have to draw the line somewhere.   The same is true in our politics.  We must have absolutes to write a law, regulate and prosecute lawlessness.   We must determine what is essential, and what form it takes.  This will create necessary conflict, but it cannot be ignored.  In late 2020 the New England Journal of Medicine published an article by a group of physicians who want sex designations on birth certificates eliminated because “they offer no clinical utility”.  Really?  I know evolutionary biologists who vehemently oppose this suggestion based on these essentialism arguments.  They use the definition of “gamete” to distinguish the proven differences between X/Y and X/X.  We essentialist do not deny the extremely rare incidence of intersex, or transsexual humans, but in fact, the male to female ratio on our planet at any given moment in time is nearly 1 to 1.  This has been proven. When we start denying, or confusing these objective and observable facts, the negative impact on our society will be enormous.