Basic endemic problems in parapsychological research include amongst others: insufficient definition of the subject matter, total reliance on negative definitions of their phenomena (E.g.- psi is said to occur only when all known normal influences are ruled out); failure to produce a single phenomenon that can be independently replicated by neutral researchers; the invention of "effects" such as the psi-experimenter effect to explain away inconsistencies in the data and failures to achieve predicted outcomes; unfalsifiability of claims; unpredictability of effects; lack of progress in over a century of formal research; methodological weaknesses; reliance on statistical procedures to determine when psi has supposedly occurred, even though statistical analysis does not in itself justify a claim that psi has occurred; and failure to jibe with other areas of science. Overall, he argues that there is nothing in parapsychological research that would ever lead parapsychologists to conclude that psi does not exist, and so, even if it does not, the search is likely to continue for a long time to come. "I continue to believe that parapsychology is, at bottom, motivated by belief in search of data, rather than data in search of explanation."