“I wanted certainty,” he wrote in his Autobiography, “in the kind of way in which people want religious faith. I thought that certainty is more likely to be found in mathematics than elsewhere” (Volume III, 1969, p.326)
The instinct for certainty is an evolutionary default* to facilitate survival.
It is this the clinging to this dogmatic ideology of certainty as influenced by Russell via Analytic Philosophy [Analytic
ism] that had dogged and hindered the progress of real philosophy.
* Whenever our primitive ancestor went hunting in the bushes and they hear the cracking sound of a twig, those who instantly are 100% certain [absolutely] there is a sable-toothed tiger around [past incidents] and then ran as fast as they could, would be more likely to survive and pass on their genes than those who ignored the sound.
This instinct for certainty is thus adapted [evolutionary] within those who continue to survive up the present.
But any sense of absolute certainty by fallible humans is a contradiction and impossibility.
Yet those driven by the primitive instinct for certainty will continue to seek certainty, e.g. a mind-independent objective reality as with the philosophical realists.