STENO'S PHILOSOPHY OF SCIENCE AND THE FOUNDATION OF GEOLOGY

Nicolaus Steno's (1638-1686) reasoning has been shown to be similar to Karl Popper's revision the positivistic philosophy of science. Steno's ‘conjecture and refutation' arguments state: Similar things are produced in similar ways and in similar surroundings. Because natural processes can obliterate as well as preserve evidence, we must build scientific reasoning on conjecture and refutation.

Steno's studies of Tuscany had taught him that the Earth had undergone huge changes. But he realized that some might construe his ideas as contradicting Holy Scripture, and that no one could believe him unless his findings were based on incontrovertible logic and observation.

He knew that Nature speaks with one voice – what Lyell later restated as the ‘Actualistic Principle', and that there were specific prerequisites for understanding geological phenomena. These he defines as types of natural motion: (1) Change in location, (2) Liquid or gaseous flow and, (3) diffusion (unknown until Steno's doctoral thesis, De Thermis, was rediscovered in Philadelphia in 1969). In addition, he defined growth as surface phenomena common to all solids including sediments, crystals and living organisms.

These made it possible for Steno to formulate the principles that earned him fame: original horizontality, lateral continuity, and order of superposition. In addition, Steno deserves credit for acknowledging the principle of cross cutting relationships (generally attributed to Hutton), and the principle of reconstruction (geologic history is a series of causes and effects known by stripping strata back from youngest to oldest).

Steno's name was nearly forgotten after his death due in part to his religious conversion. Leibniz appealed in vain to Steno to return to science from his positions as priest and bishop. To his death Steno considered scientific knowledge to be the highest praise to God and he insisted that religious speculations could never have authority above scientific arguments!