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What is Science?


Changing ideologies: monism and duality
Ernst Mayr Scientist
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Let me use the word monism, which has been used in many ways, but in this particular case it's quite appropriate: the belief that there is just one thing that explains everything, in this case it is the universal laws. Well, in biology we have a dualism which means we have the genetic… we have the universal laws and we have the genetic programme. Now this is… related to a way in which we make explanations in biology. If I, for instance, want to explain why a particular bird – let's say a flycatcher that nests here in the garden – migrates in the winter to South America, we can find that there are series of causes for this that can be reconstructed and that can be called proximate and ultimate or evolutionary causes. Proximate causes are all the physiological processes that go on, the… immediately… that have to do with the phenotype of the… of this organism and permits it to do these things, and they are mostly related to physiology. And the other set of causes… and in… in inanimate nature there is… there’s only that one set of causes which is the… the… what is related to the universal laws. The second set of causes in an organism are the ultimate or evolutionary causes or explanations, and that is this organism migrates because it has a genetic programme which tells it when the temperature drops below a certain point, or the photo periodicity reaches a certain level, then it is time for you to get moving and migrate to South America. And that again is an absolute, complete difference between organisms and inanimate matter. In… in inanimate matter they have only one set of causations, in living organisms we always have both proximate and ultimate, and a full explanation of any biological phenomenon requires the solution of both of these causations.

The late German-American biologist Ernst Mayr (1904-2005) was a leading light in the field of evolutionary biology, gaining a PhD at the age of 21. He was also a tropical explorer and ornithologist who undertook an expedition to New Guinea and collected several thousand bird skins. In 1931 he accepted a curatorial position at the American Museum of Natural History. During his time at the museum, aged 37, he published his seminal work 'Systematics and Origin of the Species' which integrated the theories of Darwin and Mendel and is considered one of his greatest works.

Listeners: Walter J. Bock

Walter J. Bock is Professor of Evolutionary Biology at Columbia University. He received his B.Sc. from Cornell and his M.A. and Ph.D. from Harvard. His research lies in the areas of organismal and evolutionary biology, with a special emphasis on functional and evolutionary morphology of the skeleto-muscular system, specifically the feeding apparatus of birds.

Tags: South America

Duration: 2 minutes, 19 seconds

Date story recorded: October 1997

Date story went live: 24 January 2008