Philosophy, Psychiatry, & Psychology

Philosophy, Psychiatry, & Psychology 11.1 (2004) 81-86

Experience, Belief, and the Interpretive Fold

Tim Bayne and Elisabeth Pacherie

We see two clusters of questions arising out of the papers in this issue. The first cluster concerns the role of experience in the explanation of delusions: Do abnormal experiences play a central role in accounting for delusions, or are they at best only marginal? And if experience plays a central role in accounting for delusions, exactly what role does it play? The second cluster of questions concerns the interpretability of delusions: Are delusional utterances meaningful, or are they mere noises? And if they are meaningful, what makes it the case that they are meaningful?

Empiricism and Rationalism

In our target paper (Bayne and Pacherie 2004) we followed Campbell in distinguishing empiricist (bottom-up) accounts of delusions from rationalist (top-down) accounts. An account is empiricist if it grounds the delusion in an abnormal experience of some kind; it is rationalist if it refuses to ground the delusion in an abnormal experience. On our reading of the literature, most recent accounts of delusions—particularly monothematic delusions—are broadly empiricist (for reviews see Langdon and Coltheart 2000; Davies et al. 2001). We took Campbell to be running against the current wave of empiricist enthusiasm in defending a version of rationalism according to which delusions arise directly from organic malfunction: according to Campbell, the abnormal experiences of delusional patients ought to be explained in terms of their delusional beliefs rather than vice versa. In response, we argued that there is much to be said in favor of empiricist enthusiasm, at least with respect to certain monothematic delusions. (There would seem to be little prospect of giving an empiricist analysis of the delusion of believing that one's left ear is a second fertile womb, for example.)

A number of the contributors to this issue are less enamored with the empiricist approach. Hohwy (2004) suggests that plausible models of delusions should be both top-down and bottom-up, and Broome (2004) claims that most contemporary models of delusion concur with Campbell's rejection of empiricism. Both Hohwy and Broome cite Frith's model of delusions of alien control as a nonempiricist model, although they present different accounts of how it is nonempiricist. Should we rethink our commitment to empiricism?

We think not. We suggest that our critics have misunderstood what we meant by top-down and bottom-up. In fact, we think that there is a lot of miscommunication in this debate. So the first order of business is to get clear on the terminology.

Begin by noting that a bottom-up approach is bottom-up from experience. Bottom-uppers need not—and in fact do not—claim that cognitive [End Page 81] biases and background beliefs play no role in the genesis of delusions. Cognitive biases can exert their influence in one (or both) of two ways: either preperceptually (by influencing experiential content), or postperceptually (by influencing the beliefs that the patient forms on the basis of their experiences). Both preperceptual and postperceptual influences are perfectly consistent with the empiricist view that the beliefs in question have their primary ground in abnormal experiences.

There are two ways in which empiricist (bottom-up) accounts of delusions can proceed (see Davies et al. 2001). According to what we called the endorsement version of empiricism, the person experiences that P and comes to believe that P. By contrast, explanationist versions of empiricism hold that the person simply has a strange experience, and comes to believe that P in an attempt to make sense of this experience. Both models are empiricist in that they hold the primary ground of the delusion to be an abnormal experience of some kind, but only proponents of the endorsement model identify the content of this abnormal experience with the content of the patient's delusion.

The distinction between endorsement and explanationist models is orthogonal to the distinction between one-factor and two-factor versions of empiricism (see Davies et al. 2001). One-factor versions of empiricism, such as Maher's (1999...