Functional Explanation In Biology Research Articles

Why did the stegosaurus have plates, or is biology second-rate because it thinks in therms of ends?

There is something distinctively different about explanation in the biological sciences, as opposed to explanation in the physical sciences. In the former one has functional arguments, arguments making reference to what Aristotle called “final causes.” As in: “The function of the plates on the back of the Stegosaurus was to keep the body at a constant temperature.” Since the Scientific Revolution, such explanations have been forbidden in the physical sciences. Does this then mean that biology is second rate, as is suggested by many including Immanuel Kant? It is argued that the Darwinian mechanism of natural selection explains why there is need of functional explanation in biology and that once this point is grasped, there is no reason to judge biology second rate.

Functional explanation and the problem of functional equivalence

The legitimacy of functional explanations in biology is threatened by a problem first identified by Hempel: the problem of functional equivalence. In order for the prevalence of a trait to be explained by its function, the function would have to explain why that very trait is prevalent and not some other functionally equivalent trait. But functions alone cannot meet this explanatory demand. I argue that this is a problem not only for Nagelian deductive-nomological models but also for etiological models of functional explanation. I contrast these models with a dual model of adaptive explanation and design explanation. This dual model largely circumvents the problem of functional equivalence, but divests functions of much explanatory power.

Reasons Explanations of Actions: Causal, Singular, and Situational

Davidson held that the explanation of action in terms of reasons was a form of causal explanation. He challenged anti-causalists to identify a non-causal relation underlying reasons-explanation which could distinguish between merely having a reason and that reason being the one for which one acts. George Wilson attempts to meet Davidson's challenge, but the relation he identifies can serve only in explanations of general facts, whereas reasons explanation is often of particular acts. This suggests that the relation underlying reasons explanation is not only causal, but singular as well. A further proposal, extracted from Fred Dretske's views, characterizes this singular causal relation in terms of non-mental triggers. But this suggestion underestimates the explanatory role of the environment at the time of action, and shares with Wilson's proposal the inability to account for the rationalization of particular acts. A situational environmentalist conception of reasons explanation, however, does not face these difficulties. Actions are often explained in terms of their reasons. Are these explanations a form of causal explanation? Davidson answers yes, and challenges those who would answer otherwise to show how, on their views, they can distinguish between merely having a reason for an action (but not acting on it), and that reason being the one for which one performs that action. Meeting this challenge is necessary for defending a genuine alternative to the causal account of reasons explanations. This paper articulates some of the significant presuppositions of Davidson's challenge and goes on to evaluate one important attempt to meet that challenge.' An interesting aspect of this anti-causalist response is its appeal to examples of teleological or functional explanation in biology and physiology as a model for a non-causal account of reasons explanation of human action. I show, however, that there is a crucial disanalogy between reasons explanation of action and the sort of explanation such examples illustrate. Reasons are often cited to explain particular acts, whereas these examples are explanations of more general facts. The disanalogy makes this strategy for a non-causal account of reasons explanation considerably less

Functional Explanations in Biology

Functional Explanations in Biology

The Logical Structure of Functional Explanations in Biology

The philosophical literature is heavy with discussions of the logical structure of various proposed schema of functional explanation (most of which are modifications of Hempel's schema [7]) but it is very light on detailed analysis of the way in which these schema actually work or the way in which they apply to the instances in which functional explanations are used by scientists. These papers use statements by scientists ascribing particular functions to particular traits, along with intuitions about the way in which ‘function’ is used in ordinary language, to ascertain the referents of the term and thus to determine the class of uses against which any schema should be tested; but such examples only show whether the schema under discussion refer to the same things as those the scientists’ refer to; they do not show whether the logical structure of the schema really captures the logical structure underlying the scientists’ use.

The logic of functional explanations

Little has been achieved in the way of providing a satisfactory analysis of functional explanations in biology and the social sciences. Hempel has demonstrated the impossibility of straightforward translation of functional statements in terms of regularity, or contrary to fact conditional statements. To cite his own example, it may be known both that the circulation of blood and the emission of noise are causally related to the pumping action of the heart, that neither effect would occur if the heart failed to pump and both effects, perhaps, may be satisfactorily explained by appeal to covering laws. Yet the biologist, though willing to assert that among other things, the heart functions to circulate blood, is disinclined to state that the heart functions to emit noise.l There are other problems that make difficult the identification of functional statements with statements of causally necessary conditions. Natural hearts may be replaced by artificial devices, thereby blocking such claims as the presence of a heart is a necessary condition for blood circulation. The same set of problems a fortiori afflict the analysis of functional discourse in the social sciences. For often, if not always, the existence of social structures have consequences which serve no apparent function. Thus, a consequence of industrialization may be air pollution or urban population concentration may result in a growing crime rate. And even when it is claimed that functions can be identified as when it is claimed that the function of religious ritual is the enhancement of feelings of group cohesiveness, functional equivalents

Functional Explanation in Biology

This paper is concerned with the problem of giving a correct analysis of function statements as they are used in biology. Examples of such statements are (1) The function of the myelin sheath is to insulate the nerve fiber and (2) The function of chlorophyll is to enable photosynthesis to take place. After criticizing analyses of such statements developed by Braithwaite, Nagel and Hempel an analysis is presented by the author. Finally the question of whether function statements are explanations is discussed briefly.