Clemson University

Sobczyk Lecture Series

Peter Richmond
Trinity College Dublin

3:30 p.m., Feb. 15, Kinard 101

*Refreshments: 3-3:30 in Martin O foyer

Title: Unraveling Mortality


Abstract: Following a little history and some definitions of mortality and the force of mortality, we introduce the ‘bath tub’ curve which seems to be almost universal in its application spanning humans, animals and inanimate objects. The curve exhibits different features during the early and later stages of life. The later stage of life for humans is well documented and follows the law first proposed on empirical grounds by Benjamin Gompertz in 1825. Using data from across the globe from a range of countries, we examine if a maximum age for the end of life can be predicted. We show how a simple toy model which brings in ideas from biology can also predict the law of Gompertz.  

Turning to the impact of social and cultural forces, we discuss the Farr Bertillon effect. Proposed in the 19th century, this conjecture says that for all age-groups, death-rate of married people is less than death-rate of non-married be they single, widowed or divorced. Never established with great accuracy, it has been considered by many to be a statistical artefact. We re-examine its validity using modern data sets from across the globe. This leads us to a more general conjecture that any abrupt change in living or social conditions generates a mortality spike which acts as a kind of selection process. This we assert applies to both living and inanimate complex objects. The conjecture will be illustrated using a few examples spanning prison inmates to fish. Even birth may be described as a shock to the fetus and data for early life is used to illustrate how character of the mortality curve differs both qualitatively and quantitatively from the later Gompertz phase. 

From considerations of causes of death in early life, we show how many diseases may be differentiated into two types characteristic of early and later life. This also illustrates the impact of medical advances over the years as well as the challenges ahead.

Finally, we use the ideas developed to compare the effect on mortality of therapies for some different diseases such as TB and cancer and offer some tentative thoughts on strategies for disease control. 

We conclude with a few thoughts about social care of the elderly.

The annual lecture series is named after the late Andrew Sobczyk, a well-known professor and researcher in the fields of mathematics and mathematical physics. It is funded by a public endowment established by Professor Sobzcyk’s family and friends. The event is sponsored by the College of Science, the School of Mathematical and Statistical Sciences and the Department of Physics and Astronomy. Refreshments will be served from 3-3:30 p.m. in the foyer of first floor Martin O. For more information, contact Elena Dimitrova at

Friday, February 15 at 3:30pm to 6:00pm

Kinard, 101
Parkway Drive, Clemson, SC 29634

Event Type



College of Science, Mathematical Sciences

Target Audience

General Public

Contact Name:

Elena Dimitrova

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