With meditation practice comes an understanding that the past and the future are not realities, just projections. You may pretend that the future is out there waiting for you, and that the past is an accessible entity. This is a false sense of dualism, since all dualistic systems are false and inorganic.
The Zen attitude towards conquering dualism is not to go against it but to transcend it entirely. You must embrace all contradictions and subsequently embrace the contradictions that result from embracing contradictions.
Life acquires a certain playful air once you come to regularly meditate on its absurdity. You don’t even need to purposefully or forcefully think about how absurd the human condition is. If you simply sit and let your thoughts float in and out, this realization will come itself. There are many great Zen stories that illustrate this absurdity, and the power of embracing a sort-of grey area in between belief and disbelief, truth and falsehood, good and evil.
These concepts shouldn’t (and can’t, really) be viewed in isolation. They exist in relation to one another, and there is no Side A without Side B. All concepts are in codependent relationships with their opposites.