My paper argues that there would be benefits for naturalistic philosophers if they expanded their methodological toolkit. The tools discussed here are the systematic methodologies for literature search and review that are widely employed in the natural, life and health sciences.
More in detail, the paper presents and defends the following claims. First, naturalistic philosophers do not philosophise in a vacuum and, in fact, rely on literature search and review in a number of ways and for several purposes. A hot topic in metaphilosophy concerns how best to describe the methods used by philosophers and their practices. Many of the recent discussions on this topic have focused on whether, to what extent, and how analytic philosophy rests on the use of intuitions. Still, we should not underestimate the importance of literature search and review for the philosophical profession, at least in many areas of philosophical investigation. More precisely, if we asked what naturalistic philosophers actually do when they carry out philosophical research, a plausible answer could not help but mention their engagement with literature search and review as an important aspect of it.
Second, biases and cognitive limitations are likely to affect literature search and review in many critical ways. Over the past decades, psychologists have described numerous ways in which judgment formation and information search can be biased, and there are no reasons to doubt that also literature search and review should be biased in important ways, and even in the field of philosophy. For instance, Roy Baumeister and Leary (1997, 319) wrote that:
Although literature reviews are less subject than empirical investigations to capitalizing on chance, they are probably more susceptible to the danger of confirmation bias. Many good literature reviews involve seeing a theoretical pattern or principle in multiple spheres of behavior and evidence, and putting together such a paper undoubtedly involves an aggressive search for evidence that fits the hypothesized pattern.
Third, scientists have come to widely adopt systematic reviews to minimise bias in the activity of literature search and review, and these tools should also be of wide interest to naturalistic philosophers. More precisely, systematic research review is a highly structured approach to cumulating knowledge. Progress in knowledge acquisition is the result of the integration of efforts, and literature reviews are vehicles for summarising research. For systematic reviews, a clear set of rules exists for searching studies and for determining which should be included in or excluded from the analysis. The reproducibility of an experimental result is a fundamental assumption in science and in a similar fashion systematic reviews aim to allow for high reproducibility of conclusions by minimising bias and maximising transparency. Notably, Cooper nicely expresses the spirit behind the systematic review movement in the introduction to his book, Synthesising Research (1998, xi):
The approach to research synthesis presented in this book represents a significant departure from how reviews had been conducted just 20 years ago. Instead of a subjective, narrative approach, this book presents an objective systematic approach. Here, the reader will learn how to carry out an integration of research according to scientific principles and rules. The intended result is a research synthesis that can be replicated by others, can create consensus among scholars, and can focus debate in a constructive fashion.
In my paper, these claims are carefully discussed, and then combined to offer a plea for a type of minimally biased philosophy: if naturalistic philosophers wish to reduce bias in philosophy, as it is assumed that they should, then they should consider ways to supplement their traditional tools for literature search and review by including systematic reviews.