When looking for problems with the DTM a good place to start is by recalling the problems that face a Direct Theory of Perception.  The most obvious and possibly most serious problem for the DTP is the problem of error.  If perceiving X as F is nothing more than having a direct awareness of X's being F, then how is it that we are often wrong in our perceptual beliefs?  To allow for the possibility of error, it seems that an account must provide space for things to go wrong.  Similarly, the DTM tells us simply that memory provides us with immediate knowledge of the past. But it doesn't seem that it always does that; after all, memory is fallible.  This “problem,” though, might not bother Reid who claims that when memory is “distinct and determinate” and when the mind is sound, then what is believed is “no less certain than if it was grounded on demonstration” [Reid 1785, Essay III, Section I].  Reid also claims, when considering a case of his remembering something from earlier in the day, “It is impossible that this act [of remembrance] should be, if the event [i.e., the event remembered] did not happen” [Reid 1785, Essay III, Section II].  So Reid might welcome the result that the DTM apparently entails the infallibility of memory (at least where what it remembered is distinct and the mind is in good working order).  But whether Reid acknowledges it or not, it surely it a problem.  Even clear and distinct “memories” in those who suffer from no psychological disorder can turn out to be false.