In our culture, it is our tendency to look to our past to tell us who we are. We often define ourselves as the sum of our past perceptions and experiences. From the perspective of Yoga philosophy, our past tells us who we are not. Our past experiences are simply experiences, but they do not necessarily define us. We can evaluate and learn from the experiences, but we do not need to identify with them and allow them to limit who we are. We can experience the experience without being the experience.
Many spiritual teachers remind us that we need to be in the moment. How do we actually practice that? It is not possible to live in the moment if we constantly identify with the past. Anticipating the future also becomes a hindrance. Being in the moment means being fully present without the filter of past and future. When the mind moves into the past or anticipates the future it projects those thoughts onto the present movement. As a result, we often don’t see things as they really are. If we have a past negative experience around a particular circumstance, then when that circumstance arises again, we tend to project the past onto the present and most likely see negativity in the present situation even it is isn’t inherently there. We mentally and emotionally set ourselves up to have a negative experience based on past experiences.
Past experiences are valid in the sense that we can draw upon them to help us grow, but when we over-identify with the past we can get stuck in certain mental and emotional habit patterns.