It was in the island's lagoon of Kolpos Kalloni that Aristotle was struck by the anatomy of fish and molluscs, and started trying to account for the function of their parts.
Leroi's vivid descriptions of the elements that inspired Aristotle's biological doctrines — places, colours, smells, marine landscapes and animals, and local lore — enjoin the reader to grasp them viscerally as well as intellectually.
Aristotle's time on Lesvos was only a chapter in a life of discoveries, and Leroi covers those signal achievements with breadth and depth.
He details the theoretical and methodological principles governing the functional anatomy of species from pigeons to tortoises, discussed by Aristotle in On the Parts of Animals , as well as the descriptive zoology expounded in his History of Animals. For instance, Leroi explores Aristotle's theory of causation, based on the distinction between material, efficient, formal and final causes.
He looks at the philosopher's views on the directedness of natural phenomena and the role played by necessity and hazard. He sketches out the theory of four elements fire, air, water and earth as the prime constituents of natural bodies. And he looks at the theory of soul and its relationship to the body — through which Aristotle accounted for aspects of physiology and psychology, from nutrition to rational thinking. Fascinating chapters are devoted to Aristotle's gradualist conception of the natural world and living things — perhaps best expressed in the saying natura non facit saltum , or 'nature does not make jumps'.
Also covered is his theory of sexual generation and transmission of hereditary traits, which he expounded in the masterful On the Generation of Animals. Despite a number of mistaken assumptions such as the lack of a female 'seed' , this theory encompasses a huge number of valuable observations and insights that laid the foundations of modern embryology.
The Lagoon traces other ways in which Aristotelian thought has permeated Western science. Leroi charts its influence on Renaissance anatomists and physiologists. The English physician William Harvey's discovery of blood circulation, for instance, was largely inspired by Aristotle's biological ideas, especially the concept of the heart as the most important organ in the body, as well as by Aristotle's empirical emphasis on investigation and demonstration.
Leroi shows how masters of comparative anatomy including Georges Cuvier — took inspiration from Aristotle in describing and comparing the parts of animals in light of their function as well as of their shape.
He compares Aristotle's theories with the thinking of taxonomists such as Linnaeus, of Darwin on evolution, and of the twentieth-century fathers of systems theory and cybernetics such as Walter Cannon and Norbert Wiener. Leroi is careful not to represent Aristotle as a precursor in crude terms, or to read him through inappropriate contemporary lenses.
Instead, he highlights aspects of Aristotle's doctrines that still 'speak' to contemporary scientists, and that have been illuminated by modern scientific understanding — for example, Aristotle's emphasis on direct observation and dissection.
As Leroi acknowledges, decades of scholarly effort by philosophers and historians such as Allan Gotthelf and James Lennox have gone into the reassessment of Aristotelian biology and its effect on the history of Western science. In this respect, the book broaches no new questions, and brings no new perspective to the heated debates among Aristotelian scholars. But that is to miss its point. The Lagoon is a wonderful introduction to Aristotle's biology, which specialists will also enjoy.
Every page is a reminder of the great beauty that we can experience by seeing the world through Aristotelian eyes. For reasons having to do with weather and equipment, the evidence collected by Eddington—and by his colleague Frank Dyson, who had taken similar photographs in Sobral, Brazil—was inconclusive; some of their images were blurry, and so failed to resolve the matter definitively.
Eddington pressed ahead anyway: the expedition report he published with Dyson contained detailed calculations and numerical tables that, they argued, showed that Einstein was right. At the time, many physicists and astronomers were skeptical of the findings.
Why did the iron rule emerge when it did? The war weakened religious loyalties and strengthened national ones. The rule simply proposed the creation of a third sphere: in addition to God and state, there would now be science. In the single-sphered, pre-scientific world, thinkers tended to inquire into everything at once. Often, they arrived at conclusions about nature that were fascinating, visionary, and wrong. Looking back, we usually fault such thinkers for being insufficiently methodical and empirical.
It never occurred to them to ask if they might illuminate more collectively by thinking about less individually. In fact, the iron rule offered scientists a more supple vision of progress.
Before its arrival, intellectual life was conducted in grand gestures. The iron rule broke that pattern. But it also changed what counted as progress. In the past, a theory about the world was deemed valid when it was complete—when God, light, muscles, plants, and the planets cohered. The iron rule allowed scientists to step away from the quest for completeness. The consequences of this shift would become apparent only with time.
Descartes would have found this attitude ridiculous. He had been playing a deep game—trying to explain, at a fundamental level, how the universe fit together. Work could continue, and understanding could be acquired on the other side.
In this way, shallowness was actually more powerful than depth. We seem to be crossing a similar bridge today. The confusion most of us feel about it is echoed, in a higher register, among physicists, who argue about whether there are many worlds or one. Without the iron rule, Strevens writes, physicists confronted with such a theory would have found themselves at an impasse.
They would have argued endlessly about quantum metaphysics. Following the iron rule, they can make progress empirically even though they are uncertain conceptually. Individual researchers still passionately disagree about what quantum theory means. Even as we wait to understand the theory, we can refine it, one decimal place at a time. One group of theorists, the rationalists, has argued that science is a new way of thinking, and that the scientist is a new kind of thinker—dispassionate to an uncommon degree.
As evidence against this view, another group, the subjectivists, points out that scientists are as hopelessly biased as the rest of us. To this group, the aloofness of science is a smoke screen behind which the inevitable emotions and ideologies hide. Strevens offers a more modest story. On the contrary, once subjectivity is channelled by the iron rule, it becomes a vital component of the knowledge machine.
On another, it makes sense that a philosopher would be attuned to the power of how we talk and argue. Despite having their own cultural view of the world, they each independently developed materials such as gunpowder, soap and paper. However, it wasn't until the 13th century that much of this scientific work was brought together in European universities, and that it started to look more like science as we know it today. Progress was relatively slow at first.
For example, it took until the 16th century for Copernicus to revolutionise literally the way that we look at the Universe, and for Harvey to put forward his ideas on how blood circulated round the human body. This slow progress was sometimes the result of religious dogma, but it was also a product of troubled times!
It was in the 17th century that modern science was really born, and the world began to be examined more closely, using instruments such as the telescope, microscope, clock and barometer. It was also at this time that scientific laws started to be put forward for such phenomena as gravity and the way that the volume, pressure and temperature of a gas are related. In the 18th century much of basic biology and chemistry was developed as part of the Age of Enlightenment.
The 19th century saw some of the great names of science: people like the chemist John Dalton, who developed the atomic theory of matter, Michael Faraday and James Maxwell who both put forward theories concerning electricity and magnetism, and Charles Darwin, who proposed the still controversial theory of evolution.
Each of these developments forced scientists radically to re-examine their views of the way in which the world worked. The last century brought discoveries such as relativity and quantum mechanics, which, again, required scientists to look at things in a completely different way. It makes you wonder what the iconoclastic discoveries of this century will be.
The table below sets out the time-scale of some of the major events in Earth history and developments in science and technology.
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