(b. San Vito del Friuli, Italy, 16 March 1687; d. San Vito del Friuli, 12 April 1764)
Moro was the son of Bernardino and Felicita Mauro. Although his early education was marked by frequent changes of instructors whose academic preparation and instruction were poor, he distinguished himself in mathematics, music, languages, literature, natural sciences, and ecclesiastical studies. Upon completion of the latter and his ordination into the ministry, he was offered a post as professor of philosophy and rhetoric at the seminary in Feltre and shortly thereafter became its director. Following the death of the bishop of Feltre and because of his own poor health, Moro returned to Friuli, where he became chapelmaster of the cathedral at Portogruaro. Of his varied interests Moro’s involvement was greatest in scientific studies, which he pursued with a Galilean conviction that the proper research methodology would inevitably, if gradually, reveal the secrets of nature.
In 1721 Vallisnieri had concluded a study of fossils with a categorical rejection of all theories on the subject, on the ground that none of them could hold up under analytical scrutiny. Moro agreed with this polemical judgment and decided to accept the challenge of the question left open by Vallisnieri. In 1740 he published his best-known work, Dei crostacei e degli altri corpi marini che si trovano sui monti, a study of the origin and development of fossiliferous deposits.
The logical order of Moro’s work reflects an empirical spirit characteristic of the enlightened intellectual climate of eighteenth-century Europe. Despite its archaic language the book is a model of cogent reasoning. Moro first provides a survey of fossil occurrence, with regional and global distribution, based on personal and reported observations. Elaborating upon earlier indications of L. Marsili and Vallisnieri, he gives a stratigraphic compilation of various fossilized marine flora and fauna, with sequential indications that preceded by almost a century the chronological intuitions of William Smith and his French contemporaries, G. Cuvier and Alexandre Brongniart.
Moro divided prevailing opinions into two groups—neptunist and nonneptunist. After singling out the most popular current opinions—the theory of total submersion and the diluvial views of Burnet and J. Woodward—for reexamination, he finally rejected them as scientifically invalid. Moro’s main objection to Burnet was that the British theologian, in Sacred Theory of the Earth, had contrived an elaborate antediluvian system in order to force proofs of conjectures established a priori as scientific conclusions.
The examination of Woodward’s theories presented a greater challenge, since the noted British naturalist had made considerable and valid contributions to the fossil debate. Moro asserted that when Woodward attempted to construct a scientific theory upon two antithetical principles, one factual (direct observation of fossils) and one hypothetical (miraculous, divine causes of geological phenomena), he violated his stated objectives and thereby undermined his preliminary observations.
Like Burnet before him, Woodward espoused the notion of an aqueous abyss, to which he ascribed, among other functions, the process of supplying water to the rivers and streams of the earth. Moro denied such hydrologic function to an “imaginary abyss,” pointing out that, among the scholars (P. Perrault, P. de la Hire, Mariotte, Purchot, J. Cassini, and, more recently, Vallisnieri, D. Corradi, and Giorgi) concerned with the origin and sources of the water on earth, Woodward alone disregarded or rejected the theory of natural precipitation as the initial source of groundwater. The most questionable theory, according to Moro, was Woodward’s theory of global disintegration, which attributed to divine intervention the loss of gravity during diluvial submersion.
Because of his plutonism Moro categorically rejected the view that stratification was caused by aqueous agents, arguing that such a view was contradicted by the evidence of both chromatic and density differentiation among layers. Unlike the Plutonist views, which were characteristic largely of the eighteenth century, the theory of total submersion had persisted from ancient times (Plutarch, Strabo) and was espoused among moderns by Fracastoro and Leibniz; Vallisnieri had also been tempted by the notion until he found it unprovable. Moro’s main objection to the theory was that it did not take into account the structural or dynamic aspects of mountain formation or land building, which were crucial to an understanding of the fossil problem.
Moro began his contribution to the fossil debate with a clear statement of his scientific credo: It is within nature that one must search for laws governing physical reality. But since nature seldom reveals efficient causes to man, one may use its constancy and uniformity and the stability of natural law to deduce from certain effects their dynamic causes, which are similar if not identical. The guiding principle and unifying theme of Moro’s theory and proof was thus the Newtonian axiom that affirms this concept: “Effectuum naturalium ejusdem generis eadem sunt causae.”
Moro noted that in order to understand his fossil theory, it was first necessary to determine the dynamic forces and physical laws involved in the formation of fossiliferous deposits. The refuted theories had been exclusively neptunist and Moro’s attitudes were exclusively plutonic, attributing geomorphological development of the globe to igneous agents. On the basis of observations made by contemporary and classical scientists of volcanic mountains and islands, Moro established a chronological framework within which he synthesized and historicized the two aspects of his theory: the formation and development of the earth and fossil phenomena. Proceeding retrospectively, he quoted from a detailed report, made to Vallisnieri by a student, G. C. Condilli, of the volcanic island of Mea Kaumem, which surfaced in the Greek archipelago near Santorini in 1707 and which continued to rise, shift, and settle until it stabilized in 1711. This, Moro noted, was but the latest incident in a long history of volcanic island formation in the archipelago, accounts of which had been left by Strabo, Pliny, and Justinian.
Historical incidents of volcanological mountain formation similarly offered proof that these land masses were the result of igneous forces within the earth. Referring to reports by N. Madrisio and Agricola, Moro cited the example of the volcanic birth in 1538 of Monte Nuovo in the Bay of Naples. On the basis of these and other historical incidents, Moro concluded that (1) mountains and islands are volcanic in origin and (2) the presence of marine fossils on the surface of these landmasses justifies the belief that the newly formed surfaces were once submerged and, in the process of rising, brought marine organisms to the surface with other materials.
Although Vallisnieri, Steno, Woodward, and F. Colonna (Hooke and J. Ray are not mentioned) had already indicated that a necessary and essential relationship exists between mountain fossils and marine organisms, Moro defended the originality of his work on the ground that he had integrated the incidental, particular observations of his predecessors into a systematic and generalized theory that correctlyplaced the problem of fossil deposits in the broader framework of mountain formation and tectonics. He also indicated that the dynamic processes involved are igneous rather than aqueous.
Moro then passed from dynamic to structural geology, describing insular mountains as massive gneisses folded in numerous directions—concave, convex, perpendicular, oblique—all caused by the pressure of intense subterranean heat. Generalizing his plutonic theory to include mainland masses, Moro differentiated these masses into two types: primary mountains—massive orthogneisses pushed up from the center of the earth when that part of the surface of the earth was submerged by water, and secondary (or stratified) mountains—composed largely of paragneisses and formed on the surface of the earth. To corroborate his distinction between volcanic and sedimentary mountains, Moro quoted Marsili, who had similarly distinguished two types of ocean floor: essential (or original) crustal rock and accidental rock, composed of sands and mineral deposits carried back to sea by returning lava flows. If the essential bedrock of the sea is similar to the massive gneisses of primary mountains, Marsili noted, it is reasonable to conclude that the latter were once a part of the ocean floor and that they were thrust above the water when that portion of the crust was still uncovered by secondary deposits.
The divergent views of mountain formation held by Moro and Vallisnieri reflect, to a large extent, the basic tensions between plutonists and neptunists, who often agreed upon structural effects but disagreed upon the dynamic principles involved. While Vallisnieri considered mountain building to be the result of successive aqueous “inundations,” Moro insisted that these “inundations” actually consisted of igneous materials, of which each successive crust is composed.
Moro attributed the striated and undulating patterns of marble to seismic action and ground shifts during the cooling and solidifying of the magma. The process of crystallogenesis, which Vallisnieri was unable to define to his satisfaction, also was interpreted by Moro as dependent upon intense heat.
The effects of volcanic action upon biological development were indicated in Moro’s consideration of the problem of skeletal remains of extinct or exotic animals in areas that are no longer a natural habitat for such species. He refuted Woodward’s diluvial explanations in favor of a surprisingly modern, naturalistic theory: that the areas of occurrence of extinct animal fossils were once their life-supporting environment. He insisted that the chronological aspect of the plutonic principle must always be kept in mind. Between volcanic eruptions, vast periods of time elapse. If the volcanic deposit is organically sterile, animal life will become extinct. As subsequent volcanic activity deposits additional strata, in which organic matter fosters the development of vegetation, the chain of being is reestablished.
Moro terminated his work with a chronological résumé of his system that is in effect a miniature composite biogeological history. Briefly, his summary is as follows: On the first day God created, among other things, the terraqueous globe surrounded by fresh water. There followed a division of the waters, without mountainous protrusions to disturb the uniform spheroid form. On the second day Moro’s concept of an active Creator as the dynamic principle is abruptly replaced by natural actualism. The shift is so sudden that one suspects that the scriptural inclusion was but a token gesture made by Moro to insure permission from religious and civic authorities to publish his work. Moro makes it quite clear that the natural potential combustibility of the core of the earth was set in motion according to divine plan or will, not according to a divine act.
Once activated, igneous pressures push up the rocky surface of the submerged lithosphere, forming primary mountains. Volcanic matter may return to the sea, depositing salts, minerals, and bitumen into the fresh water and changing its chemical composition. Secondary mountains and landmasses are built up by the same volcanic activity, with the seabed rising also as a result of the deposition of strata.
Biology also was determined by physical conditions. Marine flora and fauna were not yet formed. As the accidental seabed was transformed by mineral deposits into life-supporting systems, marine vegetation appeared, followed by marine animals, the latter with their origin and habitat in the soft earth, sand, and clay of redeposited lava flows. As landmasses built up, marine biological processes and patterns were repeated on land, with the formation of vegetation preceding that of animal life. Crowning this chain of being is man, viewed, as all else in Moro’s system, as a product of natural evolution rather than of divine creation. This audacious view of anthropogenesis by a clergyman was vehemently condemned by contemporary scripturalists. For Moro subsequent volcanic activity involved the uplift of part of the ocean floor with its flora and fauna. This in turn caused the formation of fossiliferous deposits in stratified mountains which preserved the fossils as a museum preserves evidences of human life, arts, and crafts. Superposed strata were for Moro indicative of chronological as well as environmental and cultural data.
The work provoked vehement reactions among European scientists, polarizing them into neptunists and plutonists. Among the former were Zolmann, who published his views in the Philosophical Transactions of the Royal Society in 1745, and Giuseppe Costantini, whose impassioned defense of the diluvial theory, La verité del diluvio dimostrata (1747), was so indiscriminate in its attack on Moro that it had the effects of confirming rather than disproving Moro’s views. In 1749 G. C. Generelli added his support to Moro’s theory in a paper read before the Academy of Sciences at Cremona. A German translation of the work, Neue Untersuchung über die Abanderungen der Erde (1751), was followed by a lengthy review by C. Delius in his Anleitung zu der Bergbaukunst. Moro was one of the authorities cited by Knorr (1755) and Desmarest. His scheme of periodization (primary, secondary) was amplified in Italy by Arduino and in Sweden by Bergman, who referred to Moro; by J. G. Lehmann and Pallas, in Germany and Russia, respectively; and the ultimate development was the establishment of the geologic column by A. G. Werner. Oddly enough, this work, so influential on German neptunism, made little impression on British volcanism. In 1767 E. King, in an article in the Philosophical Transactions, admitted that his geological theories had been anticipated by those of Moro, whose work he allegedly had discovered only after the publication of his own study. King’s cursory reference to Moro disappeared altogether in J. Hutton’s Theory of the Earth, which contains observations and conclusions similar to those made by Moro half a century earlier. Hutton’s ideas were influenced by the still earlier plutonic geodynamics of Hooke, and his neglect of Moro was emphasized by J. Playfair in his Illustration of the Huttonian Theory of the Earth (1802).
Moro’s work was most thoroughly analyzed and its importance emphasized by Hutton’s principal successor, Lyell.
The modernity of Moro’s views, the broad scope of knowledge that he brought to his investigations, and the breadth of the scientific fields that he examined and illuminated place him at the center of the intense intellectual activity of Italy’s “second Renaissance.”
I. Original Works. Moro’s works include Dei crostacei e degli altri corpi marini che si trovano sui monti, 2 vols. (Venice, 1740); Lettera, ossia dissertazione sopra la calata de’ fulmini dalle nuvole (Venice, 1750); and his MS “Due lettere latine sul sistema dei crostacei” (see below).
II. Secondary Literature. See A. Altan, “Memorie biografiche della terra di Sanvito,” in Memorie storiche della terra di Sanvito al Tagliamento (Venice, 1832), pp. 87–89, which also locates a number of Moro’s MSS; G. Dandolo, La caduta della Repubblica di Venezia, Appendice (Venice, 1857), p. 70; G. Generelli, “Dissertazione de’ crostacei, e dell’altre produzioni marine che sono ne’monti,” in Raccolta Milanese dell’anno 1757 (Milan, 1757), pp. 1–22; C. Lyell, Principles of Geology (London, 1830), pp. 42–47; F. di Manzano, Cenni biografici dei letterati ed artisti friulani (Udine, 1887), p. 135; Saccardo, “La botanica in Italia, materiali per la storia di questa scienza,” in Memorie del R. Istituto veneto di scienze, lettere ed arti, 25 , no. 4 (1895), 76; 26 , no. 6 (1901), 76, 114; and P. Zecchini, Vita di A. L. Moro (Padua, 1865).
See also the article on Moro in Biografia degli italiani illustri nelle scienze, lettere ed arti del secolo XVIII e dei contemporanei (Venice, 1834–1845), pp. 304–305.