SAMUEL ARBESMAN is an applied mathematician. He is currently a postdoctoral research fellow in Health Care Policy at Harvard Medical School, as well as a research fellow at the Institute for Quantitative Social Science at Harvard University. He has also been an instructor at the Harvard School of Public Health. In addition, he is the founder and director of Mesofacts.org, an initiative designed promote awareness of the slowly changing facts in our everyday life that we too often cease to continue learning after grade school. In conjunction with this, he published the article, "Warning: Your reality is out of date: Introducing the mesofact", in the Boston Globe Ideas section, which introduced the concept of timescales of knowledge.