by Greg Mayer
Robert R. Sokal, Distinguished Professor Emeritus of Ecology and Evolution at the State University of New York at Stony Brook, died at the age of 86 on April 9. During his long career he made distinguished contributions to evolutionary biology, systematics, human population genetics, and statistics, and generations of biologists have learned the principles and practices of statistical inference from the textbook he wrote with Jim Rohlf, Biometry (first edition 1969; fourth edition 2011). It was my privilege to be a student of his as an undergraduate at Stony Brook.
Mike Bell has written a fine summary of his career at the Stony Brook Ecology & Evolution website, and Joe Felsenstein also has memorialized him at Panda’s Thumb (read the comments there, too). His life story was just as, if not more, interesting than his scientific career. Born into a Jewish family in Vienna, his family fled the Nazis in 1939, and found refuge in Shanghai, China. There, he attended college, and met his future wife, Julie. They came to the United States after the war ended, and remained here. Their story, known in general terms to all at Stony Brook, was chronicled in the book Letzte Zuflucht Schanghai: Die Liebesgeschichte von Robert Reuven Sokal und Julie Chenchu Yang by Stefan Schomann (click on the title for pictures from their time in China).
He will be perhaps best remembered for his contributions to, and insistence on, rigorous, quantitative reasoning in all aspects of biology, and in helping to usher in the age of computer-based analysis of biological data. In systematics, he pioneered quantitative techniques in both phylogeny reconstruction and the assessment of similarities and differences. The latter, which he pioneered with P.H.A. Sneath, became known as numerical taxonomy. Sokal and Sneath argued that knowledge of phylogeny was not fundamental for the classificatory purposes of taxonomy, which they thought should be based on overall resemblance (an approach known as phenetics). This approach to systematics has not prevailed, but the methods developed have proved of great value throughout biology, including phylogenetics. Although he thought evolutionary considerations should not rule taxonomy, he was always devoted to the study of evolutionary questions, first in aphids, then weevils (a word he consciously strove to avoid saying, because of how it came out from a native German-speaker– something like “veevels”), then man, among other subjects. Ironically, it was some of his opponents in the taxonomic debate (the so-called transformed cladists) who seemed to lose interest in evolution, embracing a sort of Platonic idealism as the basis for what were supposedly phylogenetic methods.
At Stony Brook, he was a towering figure, always impeccably dressed in coat and tie, and with an Old World dignity and reserve, the latter reflected in the fact that, unlike all the other professors, he was known to graduate students as “Dr. Sokal”, until the students had gotten their Ph.D.’s. (There was a weekly Friday afternoon social event called the “BS”, which initials might have various meanings; officially it was the “Beer Social”, but it was rumored that it had those initials so that graduate students could refer to “Bob Sokal” before getting their degrees.) He was also superbly disciplined: on a number of occasions, a hallway conversation with him ended as we approached the elevators, because he always took the six floors of stairs down, as it was a way to regularly exercise without an interruption in his other work. But he was witty, open to discussion, and generous with his time, even for an undergraduate.
For first year Ecology & Evolution (and some other) graduate students, his biometry class was, quite literally, a rite of passage: successful students were inducted in to the “Loyal Order of Normal Deviates”, whose hymn was “Freedom By Degrees”. I was fortunate to be able to take the class as an undergraduate in my senior year (fall 1978). The second edition of Biometry was in the works, and we received the revised text in xerox. As much for his accomplishments as a researcher, he should also be recognized for his accomplishments as a teacher, both in the classroom, and through his book, which I found to be perhaps the most readable self-teaching tool I have ever encountered. I have used it (or it’s shorter version, Introduction to Biostatistics or “Baby Biometry”) for 20 years, and plan to keep using it in future classes. But last week it was my sad duty to tell my class that they are the last to use it while Dr. Sokal was alive.