As the years passed after the Darwinian revolution, and as evolution became more and more consolidated into dogma, the gestalt of continuity imposed itself on every facet of biology. The discontinuities of nature could no longer be perceived. Beyond that, scientists will need to gain a much greater understanding of the processes underlying stasis. Species stasis commonly continues for millions of years, periods of time for which environmental constancy does not seem possible. Indeed, species stasis often appears to persist despite evidence for environmental change.
Natural selection is obviously only a part of the whole picture.
Internal genetic and developmental mechanisms may play an even greater role in maintaining higher taxon-level stasis by inhibiting transitional forms from developing in the first place. If Mivart was correct in concluding that natural selection is incompetent to account for the incipient stages of useful structures, we can only criticize him for not taking his idea far enough. More importantly, we would have entered the twentieth century with theories which more accurately reflected the empirical data. We must be careful not to slip into scientism and must constantly strive to most accurately describe nature even if it means discarding some of our most cherished beliefs. Biologists must be encouraged to think about the weaknesses and extrapolations that theoreticians put forward or lay down as established truths.