The Pattern of Conversion seems to be brought on by the realization of those who thought (in the previous readings) that we were on the verge of having all of the knowledge that we will ever need. This pattern thus proves that God did not disappear, he simply was dismissed by those who chose to dismiss him.
Mill's down period prior to his enlightenment was characteristic of depression. He says that he was "in a dull state of nerves, such as everybody is occasionally liable to; unsusceptible to enjoyment" (760). Here, Mill is describing one very common aspect of depression--the loss of enjoyment in any activity in which one may be participating. His depression leads him to take shelter in reading, as he tries to self-diagnose in order to find a cure for his supposed insignificance. His taking shelter in a worldly object such as literature is a result of his "associations of pleasure with...objects of human desire" (761). This should have been a hint to him to look elsewhere for redemption.
Buckley describes the growing of a soul as "the final conquest fo doubt and despair" (774), which is supported by Mill's period of depression and questioning. If one overcomes this doubt and depression, Buckley says, they move toward "spiritual fulfillment which (is)...the solution to a deeply personal problem. The converters must work out their own problems to find God.
The interesting part of the pattern to me is the fact that after the lost person finds a faith, their problems almost immediately disappear. What none of them seem to notice is that through the pursuit of knowledge they begin to look at science as their religion. Science may be interesting, but it offers little in the way of salvation and appears bleak after life is over. The problem that these people were having was the over-reliance on a machine God, which lead to the loss of spirituality. When one loses spirituality, depression seems to me a perfectly natural effect.