If Freud had succeeded in making the unconscious a natural object suitable for scientific study, then his naturalization of the mind would be credible. The position taken here, albeit in debt to the vast critical literature, accepts that he failed. On that view, the 'mind' and 'the ego' and 'the unconscious' serve as placeholders for the corresponding targets of scientific scrutiny. On this account, the unconscious, then, is a metaphysical construction whose definition has served useful purposes, but it cannot be confused with the brain functions from which behavior emerges. This hardly denies its reality, but that reality is configured in a universe that excludes natural objects and forces. Kant, and in a different voice, Wittgenstein, considered each domain as separate and distinct, so the character of knowledge and reason employed to achieve its ends were also distinguished. In this vein, Freud's triumph rests on the successful application of 'practical' reason, when ironically he thought he was employing 'pure' reason. That misassignment accounts for Freud's error (or in Whitehead's term, 'misplaced concreteness,' to characterize this general mistake [1925]), which nevertheless yielded success. Ironically then, whereas Freud thought he was doing science, he in fact was conducting a highly novel, creative, and fecund interpretation of how humans think, conduct their lives, exhibit character and create personal identity. Simply, he conducted a moral investigation, one that remains a steadfast testimony to his insights."
Albert Tauber Freud - The Reluctant Philosopher (2010) p.127-128