Who among us does not have unpleasant experiences in his past? Being bullied in school, getting cut from an athletic team, losing a sweetheart to a rival, the premature death of a loved one, failing a licensing exam, or suffering through an ugly divorce are the kinds of painful experiences that stay with most people throughout life.

Some things we’re ashamed of, others we’re angry about. Some just sap us of our desire to move forward. But whatever our emotions about the past may be, they clog the gears of our brains and prevent us from focusing on positive, constructive ways to improve our lives.

The inability to let go of the past is a self-imposed imprisonment, an imprisonment from which only you can free yourself. For example, when the imprisonment stems from a perceived injustice you have suffered, you have two diametrically opposed options for dealing with it: (1) You can allow it to destroy the remainder of your life or (2) you can use it as a motivating force to accomplish great things.

An important aspect of letting go of the past is to continually remind yourself that despite the level of success you may achieve, the past can never be changed. If so, then let it be etched in historical stone and be done with it. There is no rational reason for allowing it to affect your life today or in the future.

The more you intellectualize these self-evident truths, the more likely they are to be adopted, through mental osmosis, by the emotional cells in your brain. This is similar to the concept of positive visualization — holding an image in your mind and thereby stimulating your body’s mechanisms to do whatever is necessary to convert that image into its physical reality.

Another excellent tool for letting go of the past is to refuse to use the word but. “I know it’s not healthy for me to continue thinking about how I got shafted in that business deal, but I just can’t stop” is a commonly heard type of comment when it comes to the challenge of letting go of the past. Or, “I know I can’t do anything about it now, but if he had given me the opportunity, I would be in a different position today.”

There are many variations to this, but the essence is always the same: In each and every case, but is used as a crutch to hang onto the past. Children should be taught at an early age that the word but is the starting point for the destructive practice of transference — blaming others for your own mistakes — which in turn is the gateway to failure. But can be an all-too-convenient escape route for the individual determined to avoid personal responsibility.

More often than not, when you eliminate the word but, you eliminate the excuse itself. Instead of relying on but, practice saying such things as, “I know it’s wrong to think about the past, so I’m going to stop” or “I know I can’t do anything about it now, which is why I’m going to forget about it.”

The only contribution the past can make to your future is through the experience it has given you, and it’s up to you to convert that experience into wisdom. Freedom from the past is essential to an action-oriented life. If your mind is cluttered with stressful thoughts about the past, paralysis tends to set in, and action dies.

In the 1946 classic The Immense Journey, Loren Eiseley says, “The door to the past is a strange door. It swings open and things pass through it, but they pass in one direction only.”

In other words, you can’t go backward in life. The past is the past, and you have only two options: Move forward or perish. On rare occasions when I’ve made the mistake of trying to get the door to the past to swing in the other direction, the results were not pleasant. And with good reason: The world, like the universe, is in a constant state of change, thus the past is never the way it used to be.

The future lies on the other side of the prison door of the past, a door you possess the power to open and step through at any time. And it’s one of the most important steps you can ever take.

That’s why I am convinced that the most rational way to live one’s life is to forget about the past and concentrate on opening new doors to the future. Best of all, unlike the door to the past, those future doors swing open quite easily — and, for the most part, you are always free to walk through them.