I think it is wrong to expect certainties in this world, where all else but God that is Truth is an uncertainty. All that appears and happens about and around us is uncertain, transient. But there is a Supreme Being hidden therein as a Certainty, and one would be blessed if one could catch a glimpse of that Certainty and hitch one's waggon to it. The quest for that Truth is the summum bonum of life.
The Bhagavad-Gita calls on humanity to dedicate body, mind and soul to pure duty and not to become mental voluptuaries at the mercy of random desires and undisciplined impulses.