THE LIFE AND WORK OF DENNIS GABOR; HIS CONTRIBUTIONSTO CYBERNETICS, PHILOSOPHY AND THE SOCIAL SCIENCES

1900 – 1979

Professor T.E. Allibone CBE, FRS.

The Dennis Gabor Memorial Lecture Given to theCybernetics Society on the

23rd of April 1985

Today we celebrate Shakespeare's birthday so, thinking of Dennis Gabor, I open my remarks with Miranda's greeting to her father. "Oh, brave new world, that hath such people in it".

Part 1 The University Years

On a lovely Easter day in 1947 as Dennis Gabor sat waiting his turn to play a game of tennis, his subliminal ego suddenly presented him with the solution to a problem which had worried him for almost a year: out of that flash of genius a new branch of physics, Holography, has evolved and a new industry is rapidly developing. Gabor was ever grateful that he had lived long enough to witness and enjoy the rich harvest that matured from those seeds he sowed 38 years ago. Holography was born in Britain but the inventor was born in Hungary. Few scientists are inventors, and this gift frequently runs in families, indeed Gabor's father, uncle and brother were all inventors. His father's family came originally from Russia, his mother's from Spain, so music and dancing, joi de vivre and happiness were inborn. Jules Verne, and that greatest of all inventors, Thomas Edison, were his boyhood idols, and his father, a leading industrialist, brought engineering and science into the home. Thus it came about that engineering was Dennis's choice for study at the Politechnic University in Budapest and from there he went on to Berlin to do research under the great engineer Professor Matthias at the Technische Hochschule at Charlottenburg. In order to record electrical transients he built one of the first high-voltage cathode ray oscillographs, focussing the electron beam with a magnetic field produced by a short solenoid. This solenoid he shrouded in iron, his first great invention, and he incorporated in the oscillograph a circuit and device by which the electrical transient tripped the oscillograph and thus, so to speak, took its own photograph. It was these two inventions that attracted me to Berlin in 1928 to meet him; I was the first Englishman he had met and from that visit sprang a friendship that I have always treasured.

College years must alas come to an end and after completing his Doctorate he left university life to join the Siemens Company in Berlin and there he began to work on a new form of electric lamp. As it happened, leaving College at that moment of time proved to be very unfortunate for him, because before leaving, he had invented the magnetic lens system for his oscillograph, and now, in Prof. Matthias's laboratory there was born the first electron microscope using Gabor's ideas of lenses to focus the electron beam, and to his great regret, he was not there; the midwives to the electron microscope were the research students he had left behind in the university.

Gabor told a story, some years later, that as he sat in a cafe in Berlin with his fellow countryman, the physicist Leo Szilard, in 1930 they discussed the wave-nature of electrons and the magnetic lenses which could focus electron beams, and they reflected upon the concept of an electron microscope but they both agreed that it would serve no purpose; you could not put living matter into a vacuum, and everything would burn to a cinder under an electron beam having an energy of, say, 100 kV. But, he wrote, "Who would have dared to believe that the cinder would preserve not only the structure of microscopic bodies but even the shape of organic molecules'? He always regretted having left the university at this time and thus having lost the chance to be in on the evolution of the electron microscope. It remained his first love for the rest of his life.

The black shadow of March 1933 fell upon the Jews in Germany so Gabor left Berlin and returned to Hungary working on an invention concerning another new form of lamp. From Budapest in 1934 he wrote to me at the Metropolitan-Vickers Electrical Company to ask if my Company could offer him employment to develop his patent. We were only a part of the large AEI Company and we were mainly concerned with heavy engineering; my research director, then Mr Arthur Fleming, suggested that I should send the correspondence to Mr Hugh Warren, the director of research of the BTH Company, the other half of AEI mainly concerned with light engineering. Warren accepted my recommendation and so it came about that Dennis spent the next 14 years in Rugby inventing an incredible range of devices, many of which unfortunately were of such complexity that they did not come to fruition; indeed you might say they were born before their time. One of his colleagues of that period, Mr. Ivor Williams, speaks of the great agility of his mind and of the tenacity with which he held on to a difficult task in spite of repeated setbacks.

During the war he was classed as an alien and had to work in a hut outside the security fence, but a continuous stream of colleagues poured into the hut to derive inspiration from his fertile mind. Dr Dyson, another of his collaborators of those days, has described some of the war work done there, of a brilliant scheme for detecting aircraft by the heat rays emitted from their engines - alas this did not quite reach the production stage of manufacture. From the hut he was obliged to take a prescribed route out of the Works but he never left the laboratory with enough time to catch the works bus. Mr. Williams describes how Dennis ran down the drive, battered trilby in hand, coat tails flying out behind him, his legs reminiscent of the emblem of the Isle of Man, to the vigorous encouragement of his fellow passengers: but no driver would have dared to have gone off and left him.

In Rugby he had no chance to return to electron optics; we in the other laboratories of the AEI Company, in Manchester and in Aldermaston, were fully engaged on developing and manufacturing the electron microscope, but Gabor kept in touch with all the work, fretting and fretting as to how to improve its resolution sufficiently to be able to see the very atoms in a crystalline lattice.

Meanwhile Scherzer had shown in 1942 that in electron lenses, neither spherical nor chromatic aberrations could be eliminated and a resolution below a few Angstrom units appeared to be impossible. This was the challenge Gabor accepted: he wrote "I had not been working in electron optics for 3 years but I must have been unconsciously digesting Hamiltonian methods and now effortlessly, I have solved the

electron trajectories. It appears that lens correction is impossible in the absence of space-charge"; and in 1946 he showed how a zonally corrected lens might be made with a central wire supplying this space-charge. He wrote the first book on the Electron Microscope during the war and in the last chapter he said he was still searching hopefully to "see" single atoms. In his own brief autobiography, which he wrote in 1957, he said: -

"I realised in 1927 that I ought to have stuck to my original line when electron optics was just discovered but I hoped it was not yet too late to make a come-back by improving the electron microscope beyond the limits set by aberration".

He admired Zernicke's use of a coherent background of waves to show up aberrations in optical lenses and he had been to see Bragg's apparatus in Cambridge, for structure analysis by interference of one beam with a coherent background of waves. Suddenly, - the story is well known, - as he was awaiting his turn to play a game of tennis with his wife in Rugby during the Easter holidays of 1947 the solution presented itself to him in a flash; his sub-conscious had been working on the problem, maybe for many months, and it delivered the answer on a platter: -

"Why not take an electron microscope picture of an object, one which contains the whole information, including the phase, a coherent background must be supplied by the same electron beam, which will therefore produce interference fringes: photograph these, and then illuminate this photograph with light and focus it onto a photographic plate".

He called the electron diffraction pattern a 'hologram' because it contained the whole information, amplitude and phase, and the magnification obtained would be the ratio of the optical to the electron wavelengths. With his very skilled assistant, Mr. Ivor Williams, he decided to try out his ideas optically, to produce an optical hologram and then reconstruct the object optically. The experiments were very tricky, indeed difficult. Monochromatic light coming through a small pinhole was weak and exposures were long, but a hologram was recorded, and when this was illuminated with the reference wave alone, the reconstruction was a good representation of the original. Gabor's full mathematical analysis of the subject written in 1948 has stood the test of time and contains all the necessary information on which holography is based.

In 1947 the AEI Company, set up a new research laboratory in the village of Aldermaston (a laboratory not to be confused with a later Government laboratory in the same village working on atomic bombs, a laboratory from which scientists and Cabinet Ministers walked away). I was in charge of this AEI laboratory; we were working on the basic science of the electron microscope, so Gabor's proposals were immediately taken up with his guidance and support: Electron holograms and optically reconstructed images were made, but only with some degree of success: I will not tell the story of this work here. We wanted him to join us on a part-time basis but the BTH Company would not allow this, and at the end of 1948 he left BTH to become a Reader in Electronics at Imperial College, London. During the next few years the Aldermaston group worked very hard on electron holography but the time

was not yet ripe, we had started 26 years too early, and for 15 years Gabor almost lost interest in holography.

Years later in America, the Laser was born and with this extremely fine beam of light very many scientists produced wonderful optical holograms, fully vindicating Gabor's invention and masterly theoretical exposition. By 1971 the world could see what a fantastic future lay ahead for holography and the Nobel Prize for physics recognised the brilliance of that inspiration on the tennis court 24 years earlier. Dennis concluded the address he gave before H.M. The King of Sweden with these words:-

"I am one of the lucky physicists who have been able to see one of their own ideas grow to a sizable chapter of physics; this has been achieved by an army of young talented research workers, and I want to express my heartfelt thanks to them for having helped me by their work to this greatest of all scientific honours".

Holography has indeed become a sizable chapter of physics. When the City University presented him with an Honorary Degree, the Orator on that occasion. Professor Walter Miller remarked that Guildhall had seen many great and varied events, and over the centuries many distinguished men had been honoured there; but there, in Guildhall, for the first time, a Nobel Prizeman received a degree, a most appropriate place in which to honour so great a scientist. Professor Miller said that a list of Professor Gabor's contributions and publications read like a syllabus for a degree course in Physics and in Engineering; and a very good course it would be!

Holography now blossoms all over the world; in Munich, the Institute for Medical Optics considers that "optics has been given new foundations" and in gratitude it has created a 'Gabor Laboratorium' for holography and Munich now boasts a Gaborstrasse. In America where he had held a high appointment at the laboratories of the Columbia Broadcasting System holography enters into many new developments that have not yet seen the light of day and there is hardly an issue of one of many scientific journals that does not record some new conquest.

In Imperial College he held a Readership, and later a Professorship relieved from any teaching or administrative duties: it has been written that he was not an administrator by temperament: how fortunate for the world, he had more time for his scientific genius to flower. In Rugby he married Marjorie Butler, also of Rugby, and they enjoyed a union of great and lasting happiness that they shared with innumerable friends who will always remember their generous warm-hearted hospitality both here and in their lovely home in Italy. They lived near to the College and this, as he once wrote, saved an hour or two of travelling every day thus giving him more time to think. He also was clean-shaven and claimed that many ideas came to him during the early morning routine of shaving so he warned the young men with beards that they might be losing great opportunities!

This change to academic life gave Gabor the greatest satisfaction: he wrote, "at last I was my own master and could work with young research students on problems of my own". His scientific output, some in collaboration with students, and some theoretical work done on his own, was considerable; 40 papers during his 10-

year tenure of the readership and another 40 after his appointment to the Chair of Applied Physics in 1958 up to retirement in 1967. Clearly I can only refer to a few of these. The tasks he set his students to do were formidable; they were almost all based on inventions. As he explained in his Professorial Inaugural Lecture in 1958: -

"It was man's ability to invent which has made human society what it is. The first step of the inventor is to visualise, by an act of imagination, a thing or a state that does not yet exist and which appears to him in some way desirable. He can start rationally arguing backwards and forwards, until a way is found from one to the other".

This had been exactly what he had done when he invented holography; holography could have been invented 50 years earlier, it involved no optics discovered in the 20th century. It merely needed inventing. Unlike the nuclear physicist for example, he was not a discoverer of new phenomena, but an inventor of things and processes. His new laboratory was superbly equipped for vacuum work and he had some excellent research students. Every one of his patents was thought out in the greatest detail before an experiment began, indeed before the problem was presented to his research pupils. Then all they had to do was to follow very detailed instructions and as they went along he watched progress with the eye of a lynx, he would repair to his typewriter and hand out further instructions based on what he had seen of the experimental work, even several times a day: if new jigs or apparatus appeared to be wanted, he would draw these and have them made. One of these students wrote to me to say, "However, we did not feel suppressed or overpowered, we had the opportunity of exercising initiative" and indeed this is where Gabor excelled; great as he was, he could, and would, listen to the less experienced, younger, person, and with great kindness, steer him along the right path of progress: "a very kind man but a hard task-master", said one student, "he demanded the utmost from himself and could not see how others could not do likewise".

One of the first big projects he gave to some PhD students was the flat T.V. tube. The concept was an old American vision of the family looking at the T.V., a thin flat "picture" just above the mantelpiece. So Gabor invented a flat T.V. "Bring 3 beams downwards sweeping them from left to right, deflect them 180 degrees upwards, and then turn them 90 degrees forwards to strike a screen of lines of 3 colours", indeed an easier concept for 3-colour T.V. than was then being developed by various companies. The electro-optical problems were great, and there were naturally many unexpected difficulties. One T.V. company had been consulted and had considered the difficulties to be too great to be worth tackling. By 1958 Gabor admitted that his students could not wholly complete this development, but he persisted with more students until 1968 by which time the patent had run out. Thirty-five years after he had invented the flat T.V. tube the Sinclair flat T.V. tube is appearing on the market, a little different from Gabor's original concept but based on the same principles.

One of his many research students was writing up his thesis and asked him how long it ought to be; Gabor replied "Well that all depends: Fermi, the great Italian nuclear physicist, wrote his on the back of a postcard but in your case I should make it a little longer".

He was appointed to a Personal Chair of Applied Electron Physics in 1958 and in the first part of his inaugural address he reviewed the work of his students over the 11 years; then in Part 2, which he called "Inventions and Civilisation" he speculated on the part which sophisticated electronic machines might be expected to play. He had always thought deeply about philosophical matters, thoughts that may well have been provoked by Aldous Huxley’s “Brave New World” published before Gabor came to England. Even during the war he had composed a kind of Hippocratic Oath for scientists, a 10-point advice as to how scientists should equip themselves to play a full part in society: as he wrote, "We represent the greatest body of men schooled in thinking in a field in which lies cannot exist, where no amount of shouting will make an incorrect mathematical solution right. We may be masters of all kinds of engineering yet be ignorant in regard to the engineering of human consent".

So in Part 2 of his Inaugural Address he spoke of electronic inventions which might write popular lyrics untouched by human brains, these would at least debunk all that is mechanical and bogus in what passes in the name of art, but he hoped that electronics would never be able to replace Beethoven. He believed predictors of the future were likely to have the greatest influence on civilisation but he warned of the dangers of social predictors taking over the manning of the State. He asked, "Do we need more inventions?" He referred to the forecasts made in a book entitled "The Foreseeable Future" written by that distinguished physicist. Sir George Thomson, and Gabor concluded by writing: -

"From a purely material point of view, a Golden Age is at hand but that there are strong forces to prevent us entering it for a few generations. Until recently the majority of people had to work hard to keep a leisured minority, but we are now, for the first time in history, faced with the possibility of a world in which only a minority need work to keep the great majority in idle luxury. Soon," he said, "the minority which had to work for the rest may be so small that it could be entirely recruited from volunteers who prefer the joys of a useful and even a dedicated life to idleness".

This leisured society of course has not yet arrived and he gave reasons why it had not; Parkinson's Law, work automatically expands so as to fill the available time, Malthus's Law, the law that a population tends to increase, up to the starvation limit, and defence, the building of devilishly ingenious products of the human mind, which, at best, will never be used and, at worst, might destroy us all. He noted that in America not long ago the majority of employees worked in agriculture, today 10% are sufficient to produce so much food that they can give away huge amounts and sell, surplus grain even to Russia; many cars are produced and are then thrown away long before they are worn out, and defence now employs a very large fraction of the working population. He spoke of Labour wanting a shorter week, 35 hours or even 24 hours but this merely to continue the same length of time at work but with more of the hours paid at over-time rates. And he asked: -

"Who is responsible for this tragi-comedy of Man frustrated by success? Who has left Man without a vision? The predictable part of the future may be a job for technology, but for the part which is a matter of free human choice it ought to be, as it was in the past, the prerogative of the inspired humanists". This is what Gabor set out to be for the rest of his valuable life.

Part 2 The Retirement Years

He was inspired to expand his views in a small book that he dedicated to one of his heroes, Aldous Huxley; he called it "Inventing the Future", a book that had a huge sale and was translated into many languages. He analysed the three great dangers which he saw facing our civilisation; war, overpopulation and the Age of Leisure; I can only mention his analyses of these briefly. Of war, he wrote of the two big powers being in the "snarling stage"; he felt certain that if the Soviets knew they would not encounter opposition they would turn Germany, France and Italy into communist states, indeed, he was writing before Russia had invaded Afghanistan just as they had invaded Czechoslovakia and his own beloved Hungary; he felt equally certain that the democracies would like to liberate Czechoslovakia, Hungary, Poland and the Undemocratic Republic of Germany from Russian oppression, but in the present stalemate neither power can change the condition of these states and the problem remains how to avoid war in the present climate of fear feeding upon fear, even though both of the big powers accepted disarmament in principle. He thought there could never be an effective defence against nuclear rockets and he scientifically analysed the magnitude of the problem but, of course, he never lived to consider the possibility of destroying warheads in outer space, a possibility only now being considered with the new technologies opening up. So Gabor prophesied a stalemate. He wrote: -

"Indifference is the great panacea of time. In 1648 the Thirty Years War came to its end by sheer exhaustion. When it started it was obvious that Europe could not exist half Protestant and half Catholic; when it came to an end it became equally obvious that this was just what Europe was to remain. It took 300 years before the Head of the Protestant Church had a friendly chat with the Pope but tolerance had long before reduced passions below the shooting level"; one might ask today, if in 1985 the Head of the West had a friendly chat with his opposite number would passions be reduced?

Of overpopulation I will quote only a few of his views, it is a subject that has been with us so long. The pill and the attitude to abortion has made a big difference in the West and he did not believe that the Head of the Roman Catholic Church would defend an obviously lost cause for long, - even only yesterday (figuratively) the State of Ireland had accepted the inevitable. But many other countries were going the wrong way, the way into starvation. He reflected that overpopulation by people was as nothing compared with the overpopulation by science; at the time of his writing, 40,000 papers in physics and 200,000 papers in chemistry were being written every year and as he wrote, the numbers were increasing at an alarming rate, soon it would be millions of papers per annum in the sciences alone.

"The libraries were bursting and dumping their surpluses in technological cemeteries and the present generation of scientists were reading rather less than the one before it; anyhow they would hardly be able to read any more as much of their time is taken up by administration and by committees".

Of the Age of Leisure he commented that Moses had shown the Promised Land to the people but had then led them around for 40 years in the wilderness until a new generation had grown up, worthy of the Land. Gabor suggested a similar period

of 40 years for the education of a generation that will deserve to live in that Age of Leisure; he wrote: -

"Every important invention unbalances the front of progress and a new invention is needed to redress the balance: disinfectants and antibiotics have strongly reduced mortality in the East," (and he could have said in Africa too) "and we need the Pill to keep it in bounds: the steam engine and the internal combustion engine are threatening our stock of fossil fuel with exhaustion so we must have nuclear power and after that thermonuclear power. We cannot stop inventing because we are riding a tiger. We must start thinking of social inventions to anaesthetize the tiger so that we can get off its back, otherwise we are either rushing headlong into catastrophe or we have to suppress inventions. As Arthur Koestler observed, every new invention is a threat to democracy, it raises psychological resistances by running counter to long-established habits and it is so tempting to overcome these resistances by coercion rather than by re-education and persuasion". Gabor wrote: "We must give up a part of national sovereignties and with this the satisfaction of nationalistic passions. We must give up the right of parents to determine the number of their children or even the right of leaving it to chance and we must reverse the present negative correlation between ability and fertility. These things must be done to avoid nuclear suicide, overpopulation and galloping imbecility. The only question is how to achieve them without dictatorial methods". He wanted social reforms to be achieved by skill; thus the alteration of our working habits was done by the simple expedient of summer time with hardly an objection. Population control, he thought, could be achieved, indeed it has been partly achieved, by child allowances and subsidies and by a change in the budget such as no child allowance to be made available after the first two children; "this whole matter must be kept away from the plane of moral passions and must be dealt with on an economic level. As for eugenics everything must be done on a voluntary basis in an attempt to eliminate hereditary diseases and improve the choice of mates". This engineering of consent in matters of policy must be achieved by rational persuasion, as he had said and for this a special talent is needed; thus Sidney Webb had imagination, ideas and high ability in planning; Lloyd George had no ideas of his own but he was a past-master in persuasion and between them was laid the foundation of the British Welfare State. Some of the planners try to prove that the present rate of increase of production can go untrammelled to the end of the century; Gabor recognised that such growth addiction may be able to defer the problems which face us now to the next generation, but by then, he feared, the problem might be no longer capable of a solution reconcilable with human freedom.

The very year that he was writing these words, pleading for control, saw the birth of the laser; this, applied to holography caused an explosion of scientific interest and thousands of papers were written on holography using laser beams. By 1971 the Nobel Committee recognised that Gabor's very original work done in 1948 rivalled that of splitting the atom or discovering the source of energy in the stars. We realise in 1985 that this new tiger, the laser, might be capable of destroying nuclear warheads in outer space, in other words, it might prevent the great powers from throwing bombs at each other.

In the few years when he held the Chair at Imperial College he and his students continued research on several lines; amongst those students was Dr. Fatmi who is well placed to give you personal impressions of life under Gabor. Many of his ideas were still far ahead of the times; one concerned a thermonuclear project of extreme complexity, a scheme far too big for him to tackle in a university laboratory and he fell ill with worry. I persuaded him to give it up and return the money to the D.S.I.R. - which he did and got better. An American observer said that, may-be; Gabor's ideas needed a quarter of a century of gestation before the scientific environment exists for them to blossom forth in full glory.

As retirement came he was invited to work in America, this he did for almost half the year, returning to England and his lovely home in Italy for the summer; he used to say that his friend Sir Thomas Merton would quote with relish a saying by J.M. Keynes "The avoidance of taxes is the only intellectual pursuit that still carries any reward". In America he devoted his great theoretical abilities to the applications of holography and produced some remarkable patents some of which he disposed of on extremely advantageous terms.

Just as he was retiring two Americans wrote a book listing 100 inventions and innovations that might have an impact on civilisation by the year 2000. Gabor decided to produce his own list with an assessment as to the desirability or otherwise of some of these. The book contains some of the views he had already expressed in his earlier book but there are a number of ideas to which I would like to refer.

First he emphasised the great acceleration with which changes had occurred. Medieval man expected his grandchildren to live as he had done, with the same values in life; the first industrial revolution changed all this, in one generation, life altered out of all recognition. In the second revolution in which we are now living the change is dramatic and the most important problems of the technology of today are not the satisfaction of primary needs, but rather the reparation of the evils and damages wrought by the technology of yesterday. Two great damages stand out; pollution of rivers and of the air we breathe. The waste products of a single factory killed all the fish in the Rhine in 1969 and there is considerable anxiety about the amount of carbon dioxide and sulphur dioxide we release into the atmosphere from our flues and power stations. Apart from the elimination of water pollution there is an urgent need for water in the arid zones and new ideas for de-salination and conservation of water below the surface are needed. Whether the content of carbon dioxide in the atmosphere caused by the burning of fuels and the reduction of forests and green vegetation might produce an appreciable change in the climate was, at that time, being hotly disputed but the anxiety is still there and new ideas are wanted to redress the imbalance created by burning fuels.

The technology of today that presents the greatest challenge is automation, and coming very quickly, automation with feedback, cybernetic machinery with which operations can be performed formerly only possible with skilled workers. Gabor wrote: -

"No one can deny that automation is capable of liberating mankind of almost all monotonous drudgery, of mining with the pickaxe, road building with

spade and wheelbarrow and mind-numbing work at the conveyor belt (so well portrayed by Charlie Chaplin in Modern Times). On the whole, the reports on the mental health of workers in automated factories are very satisfactory. But what happens to those who have been made redundant? Technologists and economists usually have two sorts of answers to this. One is that so far everything has gone well, the redundant production workers have been absorbed by the service industries and by the offices. That is perfectly true, but it reminds me of the optimist who falls from the tenth storey and by the time he reaches the third notes with satisfaction that so far it has gone well. The other answer is hardly more satisfactory: it is that redundant workers can be used in new production jobs, to produce more wealth. This is fine so long as other expanding industries are waiting for them, but are they?"

The anxiety expressed in these words in 1970 looms over us even more darkly 15 years later, so let us see what innovations he could suggest lead us to a stable, mature society, a society in which man must still have hope, a society which offers an improved quality of life if not life with an ever-increasing quantity of goods. First he placed, as he had placed before, a stable population, not necessarily to be achieved at once but no time should be wasted; he reminded us that Japan had achieved an almost stable population yet dynamic growth proceeds there. Then he considered the lot of the young manual worker, who for many years, doing the same job, earned the same pay: (that certainly was the common lot in the decade before the war when we had zero inflation). For such employees he suggested a wage rising with age, - quite apart from increases due to improved efficiency, - that is, - after all, what all professional employees, and 'white-collar' workers, had enjoyed for well over a century. He advocated a change of occupation around the age of forty with a large fraction of the population on vacation or sabbatical education courses and for a span, practising some sort of personal service, probably in uniform to engender esprit de corps. He favoured the expansion of the Open University, which was just then coming on the air, not so that the new graduate, whatever his or her age, might be able to earn more but rather so that he should acquire more knowledge and enhance his love for knowledge.

I found it disappointing that he did not advocate the complete elimination of overtime, - as is now being more urgently considered, - but when he was writing the unemployment of the very young was not as prominent as it is today. Nor did he try to spell out the economics of his innovations, - but the book is not about economics.

In an important lecture to the Institute of Metals he dwelt on the mismatch to be found in much of our industry; but of the greatest mismatch of the future, between Man's nature and the Age of Plenty he asked, "the huge increasing crime rate, the drug taking, the restlessness, are these all portents of the Age of Leisure? In due course this became the theme of his next book "The Mature Society": he reflected: -

"Because I shudder at the thought of brain washing or of taking pacifying drugs I would rather take a leaf out of the book of the successful elites of the past, such as the English aristocracy and the religious orders. I don't expect you to like it. The calculated discomfort of the English public school (cold water tubs and the like) may look like a modern version of the savage's initiation ceremony, but actually there is wisdom here in the recognition that

man does not appreciate what he gets for nothing. The permissive society is approaching a dead end. Despite the lunatic fringe, rebellious youth also contains a potential elite. For those with a fighting spirit in them, let life be hard and competitive. Everybody must be made aware that a civilisation achieved by a hundred thousand years of hard work and human sacrifice is worth preserving". He asks "Can we effect what amounts to a mutation in the nature of Man; I do not know the answer, I only know we must not give up trying and I appeal to the inventive spirit of a whole generation; inventing the correct future is infinitely more rewarding than the conquest of the planetary system".

In half the book Gabor presents data, some of which he had collected for his earlier books and then he offered a financial pathway to the new society, a path he had first suggested in 1969 when he was working with the O.E.C.D. Working Party on "Open-ended Planning". This concerned the battle between the extension of credit to create new demand and the excessive inflation that has followed deficit budgeting so frequently. When you ask "Where is the money to come from to pay for improved hospitals, public transport, the education expansion we need etc" he replies, "Where is the money coming from to pay the millions who are now paid for doing nothing and the other millions in the offices who are circulating un-necessary papers from desk to desk? If we can pay people while they are actually producing nothing why can we not pay them when they are building new towns or being re-trained for new jobs?" By offering large programmes which provide for redundant workers, he hoped as he said, optimistically, that the resistance of the trade-unions to streamlining can be overcome and that wage-demands will not be made at high levels, anticipating inflation, as they have so frequently been made before. He suggested that the state planning he advocated should be financed on the stock-market with bonds redeemable at a future date at the current industrial index value at that date, so that the investor would be safe-guarded against inflation and the bond's value would thus have an anti-inflationary effect on the exchange, - proposals which anticipated, as far as I have been able to ascertain, the present Granny Bonds available to the pensioners.

Such ideas have not yet been accepted. Instead, governments have been content to resort to ordinary deficit budgeting and then the deficit is merely added to the National Debt. You might be interested to recall how this has grown; I can just remember my father telling me about this in 1919. After the Boer War the Debt stood at £1,000M and there it stayed till 1914. The cost of the First World War was mainly paid for by taxation and the sale of our overseas assets but £8,000M was added to the National Debt so that in 1920 it stood at £9,000M. There it stayed until 1939 when the next war broke out. This war was also mainly paid for by taxes but not quite and the National Debt rose to £29,000M by 1946. We had no inflation between 1920 and 1939 but after this last war we have had severe inflation and the Debt has risen to £129,000M thus completely dwarfing all the costs of the three wars of this Century. Now it does not seem to me to matter whether you finance deficits by Granny Bonds or by adding to the National Debt. I am no economist to offer an opinion as to whether we ought to try to stop this eroding of our money or not; but doing what we have been doing since the Arabs struck in 1973, quadrupling the price of oil, has decimated our savings placed in fixed interest-bearing securities and has hit hard those folk dependent on insurance-based pensions. Doubtless a large fraction of the population would say that continuous inflation cannot be tolerated.

I must press on. The Nobel Prize in Physics came this same year 1971 and he was invited to lecture all over the world, taking Marjorie with him, but he found the time to continue patenting ideas based on holography using laser beams and he also gave a lot of time to social science. He had joined the Club of Rome, a group of 30 scientists, industrialists and humanists formed to study the present and future predicament of man in 1968, in 1970 they asked some specialists in the Massachusetts Institute of Technology to analyse five main factors that determine and will ultimately limit growth on this planet, population, agriculture, natural resources, industrial production and pollution; by 1972 they had produced a very comprehensive report called "The Limits to Growth". On the basis of this, Gabor presided over a group of 4 members of the Club to consider the controversy that had arisen over the M.I.T. report. By 1978 they had made sufficient progress to publish their first findings as a book "Beyond the Age of Waste"; very briefly they concluded that the development of nuclear energy was essential to fill the gap until new primary sources could be developed; that the present high rate of use of some raw materials must be curbed by legislation whilst further exploration is continued and that high priority must be given to food production and distribution. It is a book packed with warnings, but also with messages of hope if man will only practice restraint and care for future generations. The Director of the Institute for Advanced Studies recalls Dennis saying "The so-called Western civilisation is built on extraordinary successful technology, but spiritually on practically nothing".

For more than half his life Dennis Gabor had tried to provide spiritual guidance to others and I can think of no better words to end this tribute to him, especially on April 23rd, than the words of Mark Anthony: -

"His life was gentle, and the elementsSo mixed in him that Nature might stand upAnd say to all the world 'This was a man'.

Windsor 23rd April 1985.