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Function as "Causal Role" - Three Problems

In our previous post (check it out here): we delved into the causal-role view of function and explored why it's such an intriguing theory for many philosophers. This post is going to switch gears and touch upon some of its drawbacks and shortcomings of that theory. Now, keep in mind that we won't be diving into all the nitty-gritty details or trying to solve every problem associated with this theory. Instead, we'll give you a general overview of a few key issues to get the conversation started. These problems by no means disqualify the causal-role view from being a good theory, but they are problems to be addressed.

Remember when we discussed the selected-effects view and how it struggled with accommodating new types of functions, like exaptations? Well, the causal-role view faces a similar hiccup. Let's take a moment to recall the example we mentioned—flight as a new and unselected function for feathers. According to the selected-effects view, when birds first began to use their feathers to fly, this couldn’t be a function of the feathers, since they hadn’t evolved to have that effect. The causal-role view encounters a similar challenge when it comes to traits that no longer serve their original purpose. Take an amphibian with lungs for land survival and gills for water survival. Now imagine that a predator on land forces our poor amphibian friend to stay in the water. On the causal-role view, those lungs, which were once vital for living on land, are suddenly rendered functionless because they play no causal role in the organism’s survival. Obviously, we might argue that these organs still have a function, even if they're not currently performing it.

The second problem with the causal-role account is a normative issue. This theory tends to prioritize the causal relationships and mechanisms associated with a trait, often sidelining the evaluative and normative aspects of function. Most of us tend to believe that function should involve an evaluation of how well a trait contributes to the overall well-being of the organism or system. Unfortunately, the causal-role account overlooks this normative dimension by fixating solely on causal relationships. Of course, some might argue that normativity can be dismissed altogether, but opinions differ.

Moving on to the third problem—it seems like, on this account, everything in the universe has a function. Even, for example, a piece of bubble gum stopping up your sink! According to the causal-role view, the bubble gum's function is to prevent water from flowing through the pipe. This runs against our intuitive understanding of function. Further, we can't argue that the bubble gum is making the pipe malfunction because normativity isn't part of this account. Dysfunction, you see, relies on some notion of normativity, and without it, we're left with no tools to distinguish between function and dysfunction.

Last but not least, let's address the issue of normativity and goals. Since the causal-role account lacks a framework for normativity or a system's goals, it becomes challenging to separate functions from effects. Picture this: a tanning factory churns out loads of tanned leather but also emits copious amounts of pollution. Intuitively, we'd say that the factory's function is tanning, while the pollution acts as an unwanted side effect. But alas, the causal-role account struggles to disentangle these functions from their effects. According to this view, if the factory finds a way to stop polluting, its function changes. Sounds counterintuitive, right?

This wraps up our discussion on the problems with the causal-role account. Keep in mind that we've only touched the tip of the iceberg—there are plenty more problems associated with this theory, and plenty more solutions.

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