I will now undertake the review of the literature on Freud's philosophy of the mind-body relation that was promised in Chapter Three. Anders-son (1962) states that Freud was an epiphenominalist in 1888 and that by 1892–93 he was compelled by his clinical work to speak in terms of psychical causality which conflicts with the epiphenomenalist position. Andersson believes that Freud probably understood his mentalistic accounts of causation as provisional models ("Vorlaufigkeiten") necessitated by the relatively primitive state of neurological knowledge. Andersson cites the passage from "Gehirn" (which I have reproduced earlier in Chapter Three) in which Freud states that whether or not an item enters consciousness involves no difference in the neural processes giving rise to that mental item. Of course, such a description is compatible with epiphenomenalism, but it is also compatible with other forms of dualism.