If you absolutely need something to be true, that would be an excellent place to begin your most painstakingly openminded inquiry. For emotional investment is the hardest obstacle for the mind to overcome, and therefore the greatest bar to discovery. A philosopher, essentially, is a man whose investment in a certainty never supersedes his desire for the truth.
Consistency across time is not a life goal dictated by reason, but rather by vanity. One who is wrong, or whose understanding is simply incomplete — and there is no one whose life is not comprised largely of error and incomplete understanding — will only be harmed by an excessive concern with consistency. For a strict adherence to consistency of belief or approach is the obsession of one whose fragile ego fears self-reassessment and self-correction, or one who has simply stopped seeking completion, which is to say who has stopped living. A man who is the same person at thirty that he was at twenty, or the same person at fifty that he was at thirty, is almost certainly trapped in a web of vested interests and routinized thinking that has thwarted those natural processes of emotional maturation and intellectual self-correction which may almost serve as the working definition of human life.
The people in your life who permit and encourage your self-development are to be appreciated and cherished as your true friends. Those who would resist or discourage it, whether directly or by implicit influence, are to be avoided, or their place in your life diminished, for they have effectively become (at least in your own mind) steadfast guardians of your vested interests, and vested interests are the enemies of growth and of the search for wisdom.
Note: By “self-development” in the above, I emphatically do not mean what we late moderns call “self-expression” or “self-fulfillment.” In fact, I mean almost exactly the opposite. For the latter fashionable terms connote self-satisfaction, self-absorption, and the nihilistic relativism of “doing what pleases me.” The self-development of which I speak, and which I have associated here with maturation and self-correction, as well as with the desire for completion, entails the acceptance of a continuous and often painful struggle of self-overcoming, a willingness to cast off honors, enjoyments, and comforts, to resist the immature inclination to follow the satisfactions and ego-gratifications of any given moment, in favor of a gradual shedding of the immature and contingent inclinations toward conveniences and benefits that are confined to, and defined by, the material and temporal limits of your personal situation, which we casually call “my earthly life.” Self-development, as I mean it, is a process of detachment from the comforting delusions of “my earthly life.”