LAUSR

If we are to understand the how’s and why’s of conscious processing we need to compare it with unconscious processing and see how they differ (Baars, 1988). An accurate characterization of unconscious processing is therefore crucial for continued progression in the science of consciousness. The scope and limits of unconscious processing have been extensively investigated for more than a century (see e.g., Kouider and Dehaene, 2007, for a historical perspective), but a consensus has yet to emerge. While some argue that unconscious processing is very limited (e.g., Holender and Duscherer, 2004), others have proposed that anything that can be done consciously can also be done unconsciously (Hassin, 2013; but see Hesselmann and Moors, 2015). The controversy continues in part for methodological/technical reasons, for example that it is nontrivial to present a stimulus below the limen of consciousness while maintaining the possibility for the brain to process the information. We argue here that this aspect is particularly relevant to consider when evaluating the possibility of unconscious high-level cognitive functions: if a certain level of processing of the input stimulus cannot be verified to start with, a lack of related high-level cognition would be expected. Such situation provides little evidence against the possibility of a particular type of unconscious high-level cognition. We also argue that evidence against particular unconscious high-level functions should be framed in an experimental context where at least the conscious analog can be demonstrated—otherwise the evidence is again weak. Lastly, we note that an explicit characterization of the unconscious is crucial also in research on the neural correlates of consciousness.