The Titular Bishop of Titiopolis 
The posing of a problem in a novel way 
is a virtual prerequisite of great science 
by Stephen Jay Gould 
Modern geology began, or so the 
usual story goes, with the publication 
of a book so oddly named that it almost 
surpasses the peculiarity of the title 
later assumed by its author, Nicolaus 
Steno, a Dane by birth and a Catholic 
convert who became Titular Bishop 
of Titiopolis (in partibus infidelium) 
in 1677. (Titular bishops “preside” 
over areas in pagan hands and there- 
fore unavailable for actual resi- 
dence — in the realm of infidels, as 
the Latin subtitle proclaims. The old 
bishopric of Titiopolis is now part of 
Turkey.) As his real job, dangerous 
enough in Protestant lands, Steno min- 
istered to the scattered Catholic rem- 
nants of northern Germany, Norway, 
and Denmark. 
The book, published in 1669, bears 
a title considered “almost unintelli- 
gible” by its chief translator from the 
original Latin. It is called De solido 
intra solidum naturaliter contento 
dissertationis prodromus, or Pro- 
dromus to a dissertation on a solid 
body naturally contained within a 
solid. A prodromus is an introductory 
discourse, but Steno never wrote the 
promised dissertation because his re- 
ligious interests, following his conver- 
sion in 1667 and his ordination in 
1675, led him to abandon his distin- 
guished scientific career as a medical 
anatomist and, by fortuitous introduc- 
tion at the very end of his scientific 
work, a geologist. 
Why a solid within a solid? And 
what can such a cryptic phrase have 
to do with the origin of modern ge- 
ology? Posing a problem in a startling 
and novel way is the virtual prereq- 
uisite of great science. Steno’s genius 
lay in recognizing that a solution to 
the general problem of how solid bod- 
ies get inside other solids might pro- 
vide a criterion for unraveling the 
earth’s structure and history. But 
Steno did not formulate his problem 
by rational deduction from his arm- 
chair. As so often happens in a human 
world, he drifted toward it after an 
accidental beginning. 
Like many anatomists, Steno be- 
came interested in the resemblances 
of humans to other animals. He de- 
cided to dissect sharks and made some 
important discoveries. He demon- 
strated, for example, that the tight 
coils of the spiral intestine yielded the 
same total length (within a more con- 
fined space) as the meandering in- 
testine of mammals. In October 1666, 
during Newton’s great year, or annus 
mirabilis, and a month after London 
burned, Steno received for study the 
head of a giant shark caught at the 
city whose English name Leghorn is 
as peculiar as Steno’s two titles. (The 
name refers neither to limbs nor musi- 
cal instruments, but represents a poor 
English rendering of the old spelling, 
Ligorno, for the town now called Li- 
vorno in Italian.) Steno, like so many 
intellectuals, was working at the 
nearby city of Florence under the pa- 
tronage of Ferdinand II, the Medici 
grand duke. In examining the teeth 
of his quarry, Steno recognized that 
he had accidentally bought into one 
of the major scientific debates of his 
age, the origin of glossipetrae, or 
tongue stones. 
These fossil sharks’ teeth could be 
collected by the barrel, especially in 
Malta. In twentieth-century terms, 
their origin cannot be doubted. They 
are identical to the teeth of modern 
sharks in outward form and detailed 
structure and chemical composition — 
therefore they cannot be anything but 
sharks’ teeth. (Even our antediluvian 
creationists today do not deny it.) 
Yet the identity in form that makes 
us so certain led to another potential 
interpretation in Steno’s time — for 
God, the author of all things, often 
created with striking similarity in dif- 
ferent realms to display the order of 
his thoughts and the glorious harmony 
of his world. If he had made a world 
with seven planets (sun, moon, and 
the five visible planets of an older 
cosmology) and seven notes in a musi- 
cal scale, why not imbue rocks with 
the plastic power to form objects pre- 
cisely like the parts of animals? After 
all, the glossipetrae came from rocks 
and rocks were created as we find 
them. If the tongue stones are sharks’ 
teeth, how did they get inside rocks? 
Moreover, the earth is only a few thou- 
sand years old, and tongue stones in- 
undated European collections. How 
many sharks could have infested 
Mediterranean waters in so short a 
time? 
Steno observed that his shark had 
hundreds of teeth and that new ones 
formed continually as old teeth wore 
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