To answer this question, one first needs to understand what pathos is. Pathos is a quality one possess (or that is depicted in a text) which evokes sadness.

Stephen Jay Gould, in Women's Brains, is able to appeal to a person's pathos by beginning his essay with a quote by George Eliot. This use of Eliot's words provides two specific ways to appeal to a reader's pathos. First, George Eliot was a woman. She used a male pen name in order to insure that her words were heard and that readers would take her ideologies seriously (given women simply were not looked at as scholarly, educated, or having anything important to say). Second, the fact that a woman is showing her sadness about the fact that women are simply seen as nothing to be taken seriously.

Throughout the essay, Gould discusses the fact that women simply were not being measured fairly, if they were being measured at all. Many times throughout the essay, Gould admits that women simply were ignored.

Therefore, Gould is able to appeal to pathos given that a certain group of mankind was simply being ignored. He repeatedly states that women have been ignored throughout time and this fact alone evokes sadness in a person.

Perhaps Gould's last line can speaks most prominently to his appeal to ethos:

Woman was always the custodian of the human sentiment, morality and honor.

The fact that Gould realizes that this fact has been ignored is especially saddening.

How does Stephen Jay Gould use pathos in "Women's Brains"?

Stephen Jay Gould was an important scientist in the fields of Evolutionary Biology and Science History. His television appearances were widely watched and discussed, and his books and papers are considered essential reading in his fields.

In Gould's book The Panda's Thumb, he wrote an essay titled "Woman's Brains," in which he discussed the long-held biological theory that women -- and by extension other minorities -- are intellectually inferior to men because of the size of their brains. Gould explains previous literature, notably by Paul Broca, which used the debunked pseudoscience of Craniometrics to show how brain size affects intelligence, and gives his conclusion that variance in brain size has little-to-no effect on intelligence in humans.

To make his case stronger, Gould compares the specified case group, women, to other minority groups who have also been discriminated against in history due to the commonly held belief of inferiority. Today, discrimination against race, religion, or social status is frowned upon, but Gould explains how discrimination against, for example, African slaves was based partly on a learned belief that they were mentally inferior; similarly, women have been thought of as inferior based on many factors, including strength and temperament. By equating the incorrect scientific bias against women with similar incorrect bias against other minorities, Gould appeals to our modern emotional bias against discrimination in all forms.