Background: The increase in empirical methods of research in bioethics over the last two decades is typically perceived as a welcomed broadening of the discipline, with increased integration of social and life scientists into the field and ethics consultants into the clinical setting, however it also represents a loss of confidence in the typical normative and analytic methods of bioethics.
Discussion: The recent incipiency of "Evidence-Based Ethics" attests to this phenomenon and should be rejected as a solution to the current ambivalence toward the normative resolution of moral problems in a pluralistic society. While "evidence-based" is typically read in medicine and other life and social sciences as the empirically-adequate standard of reasonable practice and a means for increasing certainty, I propose that the evidence-based movement in fact gains consensus by displacing normative discourse with aggregate or statistically-derived empirical evidence as the "bottom line". Therefore, along with wavering on the fact/value distinction, evidence-based ethics threatens bioethics' normative mandate. The appeal of the evidence-based approach is that it offers a means of negotiating the demands of moral pluralism. Rather than appealing to explicit values that are likely not shared by all, "the evidence" is proposed to adjudicate between competing claims. Quantified measures are notably more "neutral" and democratic than liberal markers like "species normal functioning". Yet the positivist notion that claims stand or fall in light of the evidence is untenable; furthermore, the legacy of positivism entails the quieting of empirically non-verifiable (or at least non-falsifiable) considerations like moral claims and judgments. As a result, evidence-based ethics proposes to operate with the implicit normativity that accompanies the production and presentation of all biomedical and scientific facts unchecked.
Summary: The "empirical turn" in bioethics signals a need for reconsideration of the methods used for moral evaluation and resolution, however the options should not include obscuring normative content by seemingly neutral technical measure.