How can one purify something that has already happened? Many people feel that the past has made them failures or that the mistakes of others have adversely affected them. Perhaps they have memories of sicknesses or injuries that have scarred their attitudes or bodies. How, they wonder, can they possibly get rid of these scars?

To see whether it is really possible to deal with the past, let us first consider just what it is comprised of. What is its entity? What nature does it actually have? When we examine it logically in the light of Christian Science, that Science which demonstrates, in every healing it accomplishes, the mental nature of experience, we find that the past is not as solid as it seems. It is just a sort of cavalcade of mental images passing before our gaze in very much the way a film show does. The extent to which it hurts or harms us depends on ourselves, depends on how we react to it and what we make of it.

In other words, the past and its effect upon us is subjective. What we currently regard as past is an image in our own current thinking. Indeed, what we call past actually exists for us only in our current thinking—nowhere else.

We often hear it said, "What has happened has happened. It is water already over the dam, and there is nothing anyone can possibly do about it." Humanly that may seem to be so, but if we examine such thinking, we find as we have just seen, that the past exists in our current thinking, and so there is plenty we can do about it. Our current thinking can be purged and purified of any bad memory or other taint of evil.

Christian Science teaches that because God is good and infinite, evil has no basis for reality. This is true, whether the evil in question seems to be past or present or, for that matter, future. It has no basis, no reality, no form, no entity. Our hearts need to be filled with useful, good, constructive thoughts, thoughts founded on the truth of being; and God, the divine Mind, supplies them in plentiful abundance.

It does no one any good to delve into the past, to relive experiences when he seems to have been maltreated. The scientific solution is to see that the evil in such episodes is nothing but a myth. Then we will cease to be concerned or to feel that we have been penalized by them. Thus we will be radically healed of resentment and learn what is meant by forgiveness.

If we have ourselves apparently committed an injustice against others and there is no suitable human means of making amends, we may be tempted to be filled with remorse. While this is in some ways better than simply not caring, remorse is an unprogressive and unconstructive attitude, of which our thought can and should be purified. This is not done by disregarding injustices and sweeping them under the carpet. We need to see through them and realize that in the eternal law of God, Love, there has never been and can never be any provision or possibility for injustice.

With this truth we can effectively deal with beliefs of past physical illness or injury, too. It is useless and blinding to feel that in the past one has suffered from diseases or from the results of accidents to one's material body. Such an attitude is not based on the facts of being and contains nothing that will heal. It is more valuable to set about understanding that in actual fact there has never been a case of illness or accident in God's kingdom.

Sometimes when we have risen out of a belief of evil, whether attractive or unattractive, error tries its hardest to incite us and entice us back into the previous materialistic way of thinking. We have to be very alert not to heed such beckoning. Christ Jesus warns us, "No man, having put his hand to the plough, and looking back, is fit for the kingdom of God." ^{Luke 9:62;}

We can also remember the Biblical story of Lot's wife. Lot was warned of the impending destruction of Sodom, the city where they were living, and was told to take his wife and family and "escape for thy life; look not behind thee, neither stay thou in all the plain; escape to the mountain, lest thou be consumed." ^{Gen. 19:17;} As the student of Christian Science might interpret the story, he was to raise his thinking above the level of materialism and not return to it but escape to the mountain of inspiration. After they had begun to make their escape in this way, Lot's wife disobeyed the instructions. She looked back and was turned into a pillar of salt—a most unpleasant punishment!

By teaching us to wipe out of our present thinking all thoughts and memories of past evils, Christian Science effectively repudiates the whole doctrine of the fall of man, a doctrine to which religious teaching has held for many centuries. It shows that man is eternally God's child and consequently unfallen. Mrs. Eddy makes this very clear when she writes, "The relations of God and man, divine Principle and idea, are indestructible in Science; and Science knows no lapse from nor return to harmony, but holds the divine order or spiritual law, in which God and all that He creates are perfect and eternal, to have remained unchanged in its eternal history." ^{Science and Health, pp. 470, 471.}