Feminist critics have charged that Aristotle's mistaken and harmful remarks about women and slaves show inconsistency or bias-driven arbitrariness. However, this analysis shows that these remarks function within a consistent and coherent theoretical corpus. Thus, both Aristotle's hierarchical and dualistic first principles and the methodology on which his entire corpus is based must be unreliable. Moreover, consistency and coherence must be insufficient warrants of theoretical insightfulness. Aristotle's mistakes suggest caveats for feminist philosophical reconstruction.