In a world where we ought to develop - like a child develops to an adolescent then an adult - the primary importance is not to be certain about some total-truth of things.
Because, how could a child be certain about anything, when he is not yet developed? If, indeed, the child was certain about something - he would almost-certainly be mistaken.
And if we believe that we are ourselves divine and capable of communion with the Holy Ghost; that our destiny is to become more divine, to become Children of God and siblings of Jesus Christ; then this state of non-certainty will continue after biological death.
And if our God is believed to be an open-ended, learning God; whose capacity increases (forever) in response to the growing divine creativity of his Children - then uncertainty is a permanent condition - indeed a desirable condition.
What this reveals is that the quest for certainty is a delusion; an ill-formed question; a self-refuting activity - it makes no sense.
The thing is - we are at present dual beings. Before we were conscious, we were unified - living from instincts and unconsciously; but as our self-awareness developed as an alternative 'self' it took-over as the centre of our being.
So modern Man is a conscious self and a divine self; and our problem is that division.
Our destined future is again to be a divine self- but consciously so. However, since we are located-in consciousness, we begin our quest for re-unification in consciousness - and therefore this future must be consciously-chosen.
The conscious self must yield-up its supremacy, and voluntarily subordinate itself to the divine self - and despite that the conscious self can never know the 'inner-workings' of the divine self; because the divine self is a primary cause (an uncaused-cause), hence a unity and unanalysable.
Our future state of restored integration with our-selves (and The World) is therefore one in which we cause to make conscious choices! - except for the choice to follow the guidance of god-in-us. We will know what we do, but we will not, and cannot know, why we do it.
The conscious self can, if it wishes, model the divine self and make hypothesis why the divine self says such a thing. But any model is selective, simplified and ultimately false; so the conscious self can never be in a position to disprove the divine self - even though the divine self is always incomplete, and with potential to develop further; to become more divine, more comprehensive...
So, instead of seeking certainty of knowledge; we ought to seek always and at all times to think and do The Right Thing in any specific situation. We should seek to live consciously and by choice according to the dictates of the divine self; which will (in communion with the Holy Ghost) guide us to do the right thing in any specific situation, in light of our personal development and circumstances.
We cannot know for certain any particular chunk of knowledge; but we can be certain about what is the right thing for us to do, here and now.