distribution. We live our genetic code every waking moment, but it is, for the most
part, invisible to our experience. We are not aware of how our mother’s signals of
metabolic resources and our own hormonal responses shaped early life develop-
ment. As Pike points out, it is not always clear how context becomes biology (see
Pike, Chap. 2 , this volume). We grow from a clump of cells to functioning adults,
but we are generally unaware of the growth taking place. Although cumulative
growth is visible in the need for new clothes, new shoes, and new bicycles, growth
velocity is invisible unless measured frequently. When measured every single day,
what seems to be gradual growth is, when made visible, actually a series of steps of
rapid growth interspersed with periods of little to no growth (see Lampl, Chap. 4 ,
this volume).
Human biologists use other means to get inside the black box of the human
body, including sphygmomanometry (James, Chap. 8 , this volume) and clinical
assays of cortisol levels and other indicators of stress (Brown, Chap. 7 , this
volume).
Across the life span, health can be made visible by biomarkers of nutritional
status (Thomson and Crane, Chap. 9 , this volume), bone density (Gerber and
Madimenos, Chap. 12 , this volume), and other measures of physiological function.
Researchers are working to come up with effective ways to make calories“visible”
and easier to control (Lieberman, Chap. 10 , this volume). However, many things
pertaining to our bodies remain invisible and difficult to measure. As James Wood
pointed out,“the fact that something is difficult to measure is no reason not to try to
think clearly about it”( 1994 : 243–233). We are trying to think clearly about things
we can see. We are thinking about how to make visible the invisible.
A History of Inquiry
The desire to understand the inner workings of the human body is not new. Most
famously, the Greek philosopher-scientists Herophilus and Erasistratus carried out
human dissections in the third century BCE (Faulkner 2015 ; von Staden 1992 ). By
dissecting cadavers, Herophilus discovered nerves, including cranial nerves, sen-
sory, and motor nerves; identified the cornea and retina of the eye; and described
the functional anatomy of the male and female reproductive parts, including the
ovaries and fallopian tubes. Herophilus discovered heart valves, while Erasistratus
demonstrated the function of the valves and described the anatomy and function of
veins and arteries. According to Celsus, afirst-century encyclopedist, Herophilus
and Erasistratus also carried out vivisections. Celsus explained the reasoning behind
vivisections in the following:
Moreover, since both pains and various types of diseases arise in theinternalparts, they
think that no one who is ignorant of these parts can apply remedies to them. It therefore is
necessarytodissectthe bodies of thedeadand to examine their viscera and intestines.
Herophilus and Erasistratus, they say, did this in the best way by far when theycut open
people who werealive, criminals out of prison, received from kings. And while breath still15 The Shrinking Black Box of Human Biology 313