are you sure about that

Elkhart Tolle claims that life will give you whatever experience that is most helpful for the evolution of your consciousness. First of all, is that a statement from his own consciousness, is his consciousness that of bestowing sufficient for the consciousness of others, what experience in life helped him evolve that particular truth, and how does he know any of that. I like the line from a professor I once had: "50% of what will teach is the truth...I'm not sure I know which 50%". Is one's consciousness a set thing, is my present consciousness sufficient for my experience of remembering the past, knowing the present, and wondering about the future? Also, what about the fact I can only fully attend to bits of my experience, while the rest is experienced in bits and pieces? Is my experience of guilt essential to me evolved consciousness? What about what I remover from last night's dream. Will drugs impact my experience or is there a fuller aspect of my true consciousness? Are these questions essential to my consciousness?