Friday, June 08, 2007

Jenkins on Modal Knowledge

Dr. Carrie Jenkins (homepage; blog; also a TAR contributor) posted a thought-provoking draft paper on a topic I’m interested in – the question of how we acquire modal knowledge. My notes on this paper follow below.

In previous papers, Dr. Jenkins has presented a strategy intended to show how abstract (and seemingly a priori) truths can be real and yet our knowledge of these can grounded in a way friendly to an empiricist (arithmetical truths were used as a paradigm case). To give my massively oversimplifed take on this, Step 1 of her process involves our forming concepts which are seeded by and grounded in sensory input. These concepts take the pieces of world-data and extend them into maps of how the world hangs together. In Step 2, we examine and manipulate these concepts in order to extend our knowledge to what we normally think of as abstract truths. This step 2 seems to have some rationalist tint to it (where did we get this concept examination and extrapolation faculty?), but the whole package is meant to bring the process closer to an earthly explanation, and seems plausible.

But can this analysis be extended to truths regarding possibility and necessity? After all, as Jenkins discusses early in the paper, it certainly seems as if our sensory input is restricted to empirical truth values: the modal status of these truth values appears to have no detectable impact on this input. To put this in terms of the two steps above: when it comes to modal knowledge, Step 1 encompasses some mystery as well. What is it about our knowledge of the natural world which gives us the pieces to form a valid conceptual map of possibility and necessity?

She connects this problem with the issues surrounding the modal rationalist position that conceivability implies possibility. Of special concern for this paper is the basic question of why should we think that conceivability has anything to do with possibility to begin with. For conceivability to be a guide to modality, “our powers of conceiving would have to be attuned to modal fact.” (p.10)

She notes this wouldn’t be a problem if one is an anti-realist about modal truths, then we can just say they are mind dependent and just an artifact of our concepts. But we want to look at the situation facing realists regarding mind-independent modal truths. How can we explain our knowledge of such truths, including the idea that conceivability implies possibility, without invoking a special faculty of rational intuition?

What follows next is a careful review of the steps in her analytical program. She explains her take on what concepts are and how conceptual truths and falsehoods can be derived from an examination of concepts. She discusses how concepts can be grounded empirically, so they accurately represent aspects of the world. Her stance is that if concepts are grounded in this way, then examination of them can lead to conceptual knowledge.

Ok, now back to the key question for this paper: how can modal conceptual knowledge be derived from empirically grounded concepts. The distinguishing step seems to be her suggestion that in gaining empirical knowledge we gain not just atomic empirical facts, but information on the structure (or structural relations) of the actual world, and this structure can ground concepts that can be examined to gain modal knowledge. The easiest examples to work with to illuminate this idea are certain instances of necessary truths.

She uses the example “all vixens are female” to walk through the process by which the concepts (of vixen and female) are grounded empirically, and the relations between the concepts are also accurate reflections of the relations between the real features of the world represented by the concepts. The result being that when we examine the concepts we find that cannot conceive of “all vixens are female” as false; this directs us toward belief in the necessity of the proposition. Because the way we arrived at the belief was grounded in the right way, it is true. (Question: is possibility more difficult -- is it just that everything which isn't determined to be necessary is thus contingent?)

She notes that this epistemological story would need a full metaphysical theory to fill out the question of exactly why the accurate understanding of actual world structural relations leads to knowledge of modal truth, and this goes beyond the scope of the paper. But her epistemological strategy should be compatible with a number of theories.*

The paper continues with discussions of further implications and responses to possible objections. Then, as part of the concluding section, Jenkins returns to the problem raised in the beginning – that it certainly seems as though the empirical truth values can convey no sensory knowledge of modality. She says that despite its initial plausibility, there is no good reason to believe this statement is true, and this becomes clear when one considers the structure of the world, in addition to just atomic facts.

I liked the paper a lot. The richness and detail of discussion throughout (not captured in this summary) built a strong cumulative case for the argument; and the successful application of the previously developed framework to this question of modal truth speaks well for the robustness of Dr. Jenkins’ research program.

*In my case I had this idea that if I posit an ontology where the concrete world is constructed from events which are actualized possibilities, then our knowledge of these events gives us direct acquaintance with possibilities in everything that we learn (I further speculated in this post that modal knowledge gained in this way could actually precede and be constitutive of other abstract knowledge.)


Carrie Jenkins said...

Hi Steve,

In answer to your question about possibility: basically the idea with necessity is that our concepts won't allow us to conceive of a certain scenario, and so we conclude that that scenario is impossible and its opposite is necessary. With possibility the idea is that our concepts *will* allow us to conceive of the scenario. There are some problems with this that don't arise in the case of necessity (e.g.: how do we tell whether we've thought about the scenario carefully enough to allow our concepts time to kick in and prevent our conceiving of it if they're going to?) But there are similar problems that arise in the case of necessity (e.g.: how do we tell if the only reason we can't conceive of this scenario is because we're not trying hard enough?). Hope this is helpful! Thanks for your interest.

Steve said...

That is helpful, thank you. It's very nice of you to comment here.