It is possible to Attain Oneness with the Consciousness through Self-Knowledge. Having freed the self from experience of duality mentally, and staying absorbed in Consciousness" one can attain the unity with diversity.
Transforming the unreality is accessing to the ultimate truth and realizing the fact that, no second thing exist other then the soul/spirit.
With transformational understanding one will realize the fact that, the freedom that comes from letting goes of disempowering beliefs and accessing to ultimate truth. Focusing and deepening the connection with the true Self one gets freedom from experiencing the duality as reality. Accessing your Higher Truth enables you to not only experience the freedom from poor choices but allow you to experience the success that comes with making great choices. One is free from the limitations of the past, present and future, which is based on the physical self. And just as important, one is free to experiencing the birth, life and death as reality because they are part of the illusion.
The greatest realization, is one finally understands the difference between soul and my mind. Man is always the culprit, a conclusion because he is based on the false self. Inquiry, analysis and reasoning on the true base helps to uncover many untruths one is still holding as truth, that was simply not the truth any longer, and then they become unreal.