Many scientists and philosophers remain convinced that even if some questions about animal minds are empirically tractable, no amount of experimentation can provide access to  phenomenal consciousness  per se. This remains true even among those who are willing to invoke cognitive explanations of animal behavior that advert to internal representations. Opposition to dealing with consciousness can be understood in part as a legacy of behavioristic psychology first because of the behaviorists' rejection of terms for unobservables unless they could be formally defined in terms of observables, or otherwise operationalized experimentally, and second because of the strong association in many behaviorists' minds between the use of mentalistic terms and the twin bugaboos of Cartesian dualism and introspectionist psychology. In some cases these scientists are even dualists themselves, but they are strongly committed to denying the possibility of scientifically investigating consciousness, and remain skeptical of all attempts to bring it into the scientific mainstream.