Are organs functional entities? If so, what are functions?

Answer 1

Here's a brief answer: most generally, a trait's function causally explains the existence or maintenance of that trait in the population. Put differently, the function of a trait is to do whatever that trait does that caused it to be favored by natural selection (cf. Neander 1991). For example, the function of an opposable thumb is to assist in grabbing stuff because that's what opposable thumbs contributed to the fitness of organisms with that genotype. With such an account, organs have biological functions and as such, are functional entities.

Answer 2

I think the first thing to notice here is the order of your questions. A reasonable response to your first question ("Are organs functional entities?") is: What do you mean by 'functional entities' or 'function'? This suggests that the answer to the first question depends on what the answer is to the second question ("what are functions?"), and not the other way around.

There are different views of what a function is out there, but here is one you might consider. A function is (i) a disposition of some entity (the "bearer of" the disposition), which (ii) inheres in its bearer because of the way the bearer is physically, and (iii) the bearer came to exist the way it is, bearing that disposition, in order to realize (or manifest in, or engage in, or participate in, or what have you) processes of a certain type, and (iv) it came to be this way through either the process of evolution (biological functions) or intentional design (as with artifacts). This is from Barry Smith's work in ontology (http://ontology.buffalo.edu/smith/).

Now, that is a mouthful, but let's break it down a bit. A disposition is a modal property--a way something is that explains what it can do. Fragility, solubility, and skills are examples. So functions are dispositions. But what kind of disposition? A hammer is disposed to drive in nails, but also to hold down papers. Which is the function, if any? A heart is disposed to pump blood through the body, but also to make a beating sound when doing so. Which is the function, if any? The definition says functions are *just* dispositions, but ones that came about in a particular way, and somewhat *for* certain reasons (namely, so that certain processes would occur in certain circumstances). The process of driving in nails with the hammer explains why the hammer came to be how it is physically, with the disposition to drive in nails. Holding down paper does not. The process of pumping blood through the body explains why the heart came to be the way it is, such that it is disposed to pump blood. The beating sound does not. Hence, the disposition to drive in nails is the (artifact) function of the hammer, and not its disposition to hold down papers. Similarly, the disposition to pump blood through the body is the (biological) function of the heart, not the disposition to make beating sounds. Note that the functions are *dispositions*--modal properties of the objects--and not the actual processes that realize or manifest those dispositions. The driving in of nails is the function*ing* of the hammer and the actual pumping of blood through the body by the heart is the function*ing* of the heart. Functions are realized in functionings.

So, on this view, organs can have functions. They are dispositions of those organs towards certain processes (pumping blood through the body, producing insulin, providing visual input, and so on), where the occurrence of those processes help to explain why the organ bearing the disposition came to exist as it does, bearing that disposition. The organ participating in those processes is what the disposition is *for*. Again, there are other views of functions. So the main point is to make sure to have a view of function first, preferably one that is independently motivated and defended, and then decide whether that view of functions produces the result that organs have functions.

Hope this helps.