• Aster Hoving

Progress and Principle: Tidal Science

In their study of intertidal existence of the Pacific coast of North America, Between Pacific Tides (1939), Ed Ricketts and Jack Cavin make the following statement about scientific determination and observation of intertidal communities:

“To summarize, then, chance may play an important role in determining what species will be found in any given location. The history of a site may also play a role, often through adult-larval interactions. Furthermore, since intertidal communities are dynamic entities, progressing in some cases through a series of developmental or historical stages, we should keep in mind that we are usually observing only one slice of a temporal sequence. Finally, changes occurring along various scales of time and space are an essential part of the natural scene. Such local and temporal variations are far from merely inconvenient deviations in more general principles (e.g. competition, predation, etc.). Rather, the variation is itself a principle.”[1]

What this quote implies, in an epistemological sense, is that the progressive development of the science of the tides cannot be one which in a linear fashion works toward an end, or an all-encompassing knowledge of the tides. The authors emphasize that the temporal and spatial bounds of observation and measurement and the element of chance in the manifestation of intertidal communities resist generalized principles, since their principle is variation.

What this might mean for an interpretation of the development of tidal science since Guillaume Brouscon’s tidal Almanacs from c. 1375, diagrams in signs supposed to be understood by illiterate fishermen,[2] to 17th century tidal clocks,[3] to the development of ever more intricate data-analysis and satellite observation in the 20th and 21st century,[4] is that these are not progressive steps toward complete knowledge, but rather variations in ways of measuring slices of time.

Though David Edgar Cartwright, in Tides: A Scientific History (1999) which chronicles the development of tidal science, claims that “the long saga of research of quantifying the tides was finally resolved by a combination of high-speed computers and satellite radar technology”,[5] he also states the following:

"However, although tide-table production may now seem to be a routine computer operation, such work will always require expert supervision by a tidalist (as distinct from a computer technician), and a background of research into how best to extract prediction parameters from noisy data."[6]

The very page on which Cartwright claims that computers and satellites have solved the problem of quantifying the tides, he also states that the process of quantifying the tides requires knowledge not quantifiable. That which Cartwright designates as noise is itself the principle – scientific, abstract, universal parameters seem to be mysteriously extracted from it.

[1] Edward Ricketts and Jack Calvin, Between Pacific Tides, 486 [2] David Cartwright, Tides: A Scientific History, 18 [3] Cartwright, Tides, 20 [4] Cartwright, Tides, chapter 11-14 [5] Cartwright, Tides, 268 [6] Cartwright, Tides, 268


Cartwright, David Edgar. Tides: A Scientific History. Reprinted. Cambridge: Cambridge Univ. Press, 2001.

Ricketts, Edward Flanders, Jack Calvin, Joel W. Hedgpeth, and David W. Phillips. Between Pacific Tides. 5th ed. Stanford, Calif: Stanford University Press, 1985.