Let us now consider memory. No one has been able to..........to the most imaginative of scientists only a century ago.

Let us now consider memory. No one has been able to form a reliable estimate of the number of facts or impressions the brain can store during a lifetime. There is considerable evidence that we never forget anything; we are just unable to put our hands on it at the moment. We seldom encounter really impressive feats of memory these days, because there is little need for them in our world of books and documents. Before the invention of writing, all history and literature had to be carried in the head and passed on by word of mouth. Even today, there are still men who can recite the whole of the Bible or the Koran, just as once they could recite Homer.

The work of Dr Wilder Penfield and his associates at Montreal has shown, in a dramatic fashion, that long-lost memories can be revived by the electrical stimulation of certain areas of the brain, almost as if a movie record were being played back in the mind. The subject relives, in vivid detail (colour, scent, sound) some past experience -- but is aware that it is a memory, and not a present occurrence. Hypnotic techniques can also produce similar effects, a fact which was used to advantage by Freud for the treatment of mental disorders.

When we discover how the brain manages to filter and store the blizzard of impressions pouring into it during every second of our lives, we may gain conscious or artificial control of memory. It would be no longer be an inefficient, hit-and-miss process; if you wanted to re-read a page of a newspaper you had seen at a certain moment thirty years ago, you could do just that, by stimulation of the proper brain cells. In a sense, this would be a kind of time-travel into the past -- perhaps the only kind that will ever be possible. It would be a wonderful power to possess, and -- unlike many great powers -- would appear to be almost wholly beneficial.

It could revolutionize legal procedures. No one could ever again answer 'I've forgotten' to the classic question, 'What were you doing on the night of the twenty-third?' Witnesses could no longer confuse the issue by accounts of what they thought they had seen. Let us hope that memory stimulation would not be compulsory in the law courts, but if anyone pleaded this future version of the Fifth Amendment, the obvious conclusions would be drawn.

And how wonderful it would be to go back through one's past, to revive old pleasures and, in the light of later knowledge, mitigate old sorrows and learn from ancient mistakes. It has been said, falsely, that a drowning man's life flashes before his eyes. Yet perhaps one day, in extreme old age, those who no longer have any interest in the future may be given the opportunity of reliving their past, and greeting again those they knew and loved when they were young. Even this, as we shall see later, might be not a preparation for death but the prelude to a new birth.

Perhaps even more important than the stimulation of old memories would be its inverse -- the creation of new ones. It is hard to think of any invention that would be more valuable than the device which science- fiction writers have called a Mechanical Educator. As depicted by authors and artists, this remarkable gadget usually resembles the permanent-wave machine at a ladies' hair-dressers, and it performs a rather similar function - though on the material inside the skull. It is not to be confused with the teaching machines now coming into widespread use, though one day these may be recognized as its remote ancestors.

The Mechanical Educator could impress on the brain, in a matter of a few minutes, knowledge and skills which might otherwise take a lifetime to acquire. A very good analogy is the manufacture of a gramophone record; the music may have taken an hour to perform, but the disc is stamped out in a fraction of a second, and the plastic 'remembers' the performance perfectly. This would have appeared impossible, even in theory, to the most imaginative of scientists only a century ago. From Profile of the Future by Arthur C. Clarke

Summary: While no reliable estimate has been made of memory power, there is evidence that we forget nothing, though at times we fail to reach the store in the brain. Today, books and documents preclude the need for memory feats.

Electrical stimulation and hypnotism, by triggering memory, help the subject recall past experience in all its detail. By discovering the process of transmission of impression into the brain, we can control memory, and by stimulating the right brain cells we can time-travel into the past. It will be a wonderful and beneficial power to achieve. Memory stimulation can be effectively used in law courts. We can also relive the past -- a boon to the old to find solace by reviving the past. We can also create new ones. The Mechanical Educator, now in the realm of science fiction, can transfer to the brain knowledge and skills in a few minutes.