What reductionists of every stripe, including naive materialists, behaviourists, psychologists and cognitive scientists who claim the psyche or cognition is illusory, even those focused solely on pragmatic common sense who will not admit that anything is beyond its reach, is that to take an ontological position, which is to claim that something either is or is not, requires not only that the position taken accounts for the subject matter, but that it accounts for the ability to explicate the subject matter, and further that it accounts for being able to take an ontological position in the first place.
As an example of what this means, while the data gathered by cognitive science may or may not demonstrate the existence of cognition, the abililty to comprehend the data and explicate it is absolutely reliant on cognition occurring. The same goes for psychologists and the psyche. The further implication is that not only is there a psyche, which in some sense is cognitive, that cognition and the psyche must be disclosed to themselves insofar as that and what they are prior to there being a possible study of either.
Not only must ontological understanding respond to such disclosure prior to anything becoming a possible “object” for rational analysis, it necessarily occurs prior even to any perception that includes an awareness that what is perceived is being perceived. Since ontology is the basis of philosophy, all science and even common sense pragmatism remain dependent on the philosophy they facilely claim is either irrelevant or superseded, without bothering to think through the implications.