 Jenkin further asserted that once selective pressure was removed, the population would revert to its original condition.He then introduced the 'swamping argument' to deny the possibility that an occasional monstrous individual, a saltation, could supply an escape from this state of affairs and give rise to a permanent adaptation.Jenkin made a mathematical calculation for his argument

Jenkin made a mistake in his calculation stating the chances are “fifty to one” where it should have been “ten thousand to one”.