The answer I found had to do with De Morgan's views of how we know things. Most things, however, we know only contingently . Joan's life was inexorably changed by her experiences. My sabbatical time as Ned's mother had left its mark. I constantly felt De Morgan's judgment of me as a woman working in a man's world, and as I read his letters I found myself judging him in return.
Wives are, after all, merely relative.
So, I realized, are mothers. I found this to be a fascinating, engaging, thought-provoking book. W. H. Freeman and Company, 2000. She is interested in the preparation and professional development of mathematics teachers and teaches classes for them such as geometry, history of mathematics, algebra, modeling. She has a long-standing interest in the history of mathematics and in particular the place of women in that history.