According to Osho, past lives can be known because nothing experienced is ever lost; memories persist in the deep unconscious and can be accessed through disciplined regression—hypnosis or deep meditation—after first retracing this life back to conception. Yet nature wisely veils them; premature recall can overwhelm and unbalance the mind. Approach only with understanding, guidance, and purpose, not curiosity; Mahavira and Buddha pioneered such remembrance.
Yes—you can remember past lives, but those memories are very deep, so use careful guidance and go slowly or it can be upsetting.