Gould begins his book with a story of the ancient Greek philosopher, Socrates. In this story, Socrates admits to telling the citizens of Athens a false myth in order to create a peaceful social order. The myth tells of God creating humans in three separate and unequal classes; these classes determine what work humans are able to do. Those who are part of the gold class are destined to be rulers, those who are part of the silver class are only fit to assist the rulers, and those who are part of the bronze class can never be more than craftsmen.
Though Socrates tells the citizens of Athens only a myth, Gould believes the effects of this myth have shaped Western society and the concept of “biological determinism” today. Biological determinism is the view that an individual’s mental and physical traits are dictated by their genetic inheritance. It is this topic that Gould focuses on and attempts to debunk throughout the rest of the book.
Because biological determinism is a wide-spread topic, Gould chooses to focus only on the claims biological determinists make about intelligence. These claims, according to Gould, are based on two central fallacies. The first fallacy is reification, taking an abstract concept and treating it as if it were real. In the case of intelligence, the abstract concept is the mental traits of an individual. Over time, these mental traits have been labeled by scientists as “intelligence.” The second fallacy is ranking, ordering things in a hierarchical manner. Scientists have quantified intelligence in various ways over time. In the 19th century, they measured the anteroposterior diameter of human skulls (assuming a larger skull diameter correlated with a smarter person), and in the 20th century, they measured performance on standardized tests (assuming higher scores correlated with superior intelligence) to determine an intelligence quotient. This intelligence quotient, or IQ, has since been used by biological determinists to rank groups of individuals and to demonstrate the relative inferiority of a class, ethnicity, race, or sex compared to others.
According to Gould, the attempt made by scientists to reify and rank intelligence between groups based on “fact” is the true mismeasure of man; this forms the premise of his book. The reification and ranking of intelligence is, indeed, not based on any “fact”; rather, it is a concept made up by biological determinists whose a priori assumptions and pre-existing views may be distorting what they believe to be true and leading them to invalid conclusions. Gould acknowledges scientists cannot help but be influenced by culture and society, but they must acknowledge their pre-existing cultural views may be influencing the way in which they conduct studies and interpret data. Only if they are aware can they correct for it, and only after they realize no human is perfectly objective can they be truly impartial.