In summarizing his thesis, Ducasse says, ". . . psychological events can be actually experienced only in the order of their respective degrees of liveness, and thus of recency. . . . This entails that the time-series of psychological events has intrinsic direction." (See 6, p. 389.) The first point to be made here is that the connection between liveness and recency has not been established as Ducasse says it has. It seems quite possible for an earlier event to have more liveness than a later event. One remembers his last birthday more vividly (inferring this is related to liveness) than the day after it. Thus, liveness is not necessarily concurrent with recency. From this emerges a second point concerning the "intrinsic direction" of psychological events. It is conceivable that a person's experiences could exhibit an inverse relation between recency and liveness. Ducasse has given no argument against such a possibility. Thus, there seems to be no entailmerit that psychological events have intrinsic time direction.
It is probably evident how Ducasse uses his theory to resolve the causal paradox involved in precognition. Physical events, by themselves, do not categorically have pastness, presentness, or futureness. When a given physical event is precognized and precognition of it is a psychological event, then the physical event receives presentness, not before. Thus, there can be no problem of a nonexistent event causing something to be in the present. As soon as an event is precognized, it is present.
Aside from attacking Ducasse's method of definition, there are several approaches one can take. The following is one of the less obvious objections. An essential feature of Ducasse's scheme is that physical events, by themselves, do not have futurity. Thus, he can solve the problem of precognizing physical events. He cannot, however, handle the precognition of purely psychological events -- events which would have pastness, presentness, etc., independent of the precognition of them. An example is precognitive telepathy, the precognition of someone's thoughts.
In summary, Mundle, Broad, and Ducasse all deny that precognition is a logical possibility. From the above analysis it should be clear, however, that if precognition is to be rejected as a logical possibility it will have to be on grounds other than those offered by the three philosophers discussed.