The Dynamics of Scientific Knowledge - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 14

Fig. 1.2 Computer-generated “best fit” of the continents. There are several versions of this type
of fit maps credited to the British geophysicists E.C. Bullard, J.E. Everett, and A.G. Smith
The matching coastlines of continents around the Atlantic Ocean become
strikingly apparent in computer-fitted maps. The computer fit was made at the
1,000-m (500-fathom) submarine depth contour, which provided the best fit of the
coastlines. Such computer fits find the best result by finding the depth contour that
minimizes both the overlaps and gaps between the continents (See Fig. 1.2 ).
Wegener's theory was received well by many European geologists. The English
geologist Arthur Holmes (1890-1965) pointed out that the lack of a driving force
was hardly sufficient grounds to ditch the entire concept. Around 1930, Holmes
proposed the power of convection as a mechanism to explain Wegener's continental
drift. He suggested that currents of heat and thermal expansion in the Earth's mantle
could make the continents move toward or away from one another and create new
ocean floor and mountain ranges. Wegener died in 1930. Holmes was a little too
late to support Wegener. On the other hand, Holmes was about 30 years too early
to back up his theory with hard evidence. On the hindsight, Holmes had come very
close to the modern understanding of Earth's plates and their dynamics.
The difference between Wegener's theory and the contemporary conceptual
systems is highlighted in Fig. 1.3 . Paul Thagard draws our attention to how
Wegener's continental drift theory (Fig. 1.4 ) differs from the conceptual structure of