Teleological explanation and the Darwinian argument

Abstract

ENGLISH ABSTRACT: Darwin's development of his theory of descent with modification by natural selection effected a profound transformation of teleological thinking in biology. In what sense, and through which means his theoretical discoveries can be said to have overcome metaphysical teleology and to have initiated and informed current ideas on what scientifically legitimate "teleological" explanation in biology should consist of, is the question investigated by this thesis. Two main claims (which are really two sides of the same coin) are being defended: In the first place, the contention is that Darwin's efforts to elaborate a theory of evolution that could comply with the requirements of a certain empiricist (vera causa) philosophy of science, enabled him to undermine metaphysical teleological explanation in biology. Through having posited natural selection as the empirical causal process responsible for all the wonderful features of living phenomena, Darwin dispensed with the need for appeals to revealed theology's argument from special creation, as well as with appeals to natural theology's argument from design. The collapse of these kinds of metaphysical explanation was an important precondition for the emergence of any properly scientific account of adaptational phenomena, that is to say, of any scientifically legitimate model of "teleological" explanation. In the second place, the contention is - and this again by virtue of the kind of empirical historical process he envisaged as the cause of adaptations - that Darwin indeed initiated such a new scientifically legitimate model of teleological explanation. Darwin provided teleological explanation, for the first time, with a proper causal basis (natural selection) - a crucial legacy to present-day biology. However, the explication of that model had to wait until well into the present century. It now goes under the name of an etiological approach to goals and functions, and is the model which, in my view, not only offers the closest approximation to Darwin's own conceptualisation of the explanation of adaptational phenomena, but which is, moreover, the most fundamental model for both explanatory and historical reasons. Finally, given Darwin's initiating of the latter model, we can now seriously consider altogether discarding the designation "teleological" when speaking of current biological explanation of apparently functional and goal-directed phenomena.

AFRIKAANSE OPSOMMING: Darwin se ontwikkeling van sy teorie van evolusie deur natuurlike seleksie het 'n diepgaande transformasie in teleologiese denke in biologie teweeg gebring. Die vraag aan die orde in hierdie tesis het betrekking op die sin waarin, en die wyse waarop, Darwin se teoretiese ontdekkinge metafisiese teleologie oorkom het, en ook kontemporere idees oor hoe wetenskaplik legitieme "teleologiese" verklaring in biologie daar moet uitsien, geinisieer en informeer het. Twee hoofaansprake (wat in werklikheid twee kante van dieselfde munt is) word hier verdedig: Eerstens, word geargumenteer dat Darwin se pogings om 'n teorie van evolusie te ontwikkel wat kon voldoen aan die vereistes van 'n bepaalde empiristiese (vera causa) wetenskapsfilosofie, hom daartoe in staat gestel het om metafisiese teleologiese verklaring in biologie te ondermyn. Deur natuurlike seleksie aan te bied as die empiriese kousale proses verantwoordelik vir al die merkwaardige eienskappe van lewende fenomene, kon hy wegdoen met beroepe op openbaringsteologie se argument van besondere skepping, sowel as met beroepe op natuurlike teologie se argument van ontwerp. Die ondergang van hierdie soort metafisiese verklarings was 'n belangrike voorwaarde vir die ontwikkeling van 'n werklik wetenskaplike beskouing van adaptasiefenomene, dit is, van 'n wetenskaplik legitieme model van "teleologiese" verklaring. Tweedens, word geargumenteer - en weer eens kragtens die empiriese, historiese proses wat hy voorgestel het as die oorsaak van adaptasies - dat Darwin inderdaad so 'n nuwe en wetenskaplik legitieme model van teleologiese verklaring ge·inisieer het. Hy was die eerste om teleologiese verklaring van 'n behoorlik kousale basis (natuurlike seleksie) te voorsien - 'n belangrike erfiating aan hedendaagse biologie. Nietemin, die eksplikasie van die model moes wag tot relatief onlangs in die huidige eeu. Dit gaan nou onder die benaming van 'n etiologiese beskouing van funksies en doelwitte, en is die model wat na my mening nie net die beste benadering bied van Darwin se eie konseptualisering van die verklaring van adaptasie-fenomene nie, maar wat ook die mees fundamentele model is - vir beide verklarings- en historiese redes. Ten slotte, gegee Darwin se inisiering van laasgenoemde model, is dit nou moontlik om ernstige oorweging te gee aan die gewensdheid al dan nie van voortgaande gebruik van die benaming "teleologies" wanneer dit gaan oor hedendaagse biologiese verklaring van skynbaar funksionele en doel-gerigte fenomene.