La misura del tempo biologico
‘There is surely nothing other than the single purpose of the present moment.
A man’s whole life is a succession of moment after moment. If one fully understands the present moment, there will be nothing else to do, and nothing else to pursue.’
—— Yamamoto Tsunetomo, Hagakure
‘Time is not a line, but a series of now-points.’
—— Taisen Deshimaru
‘Time has no division to mark its passage, there is never a thunderstorm or blare of trumpets to announce the beginning of a new month or year. Even when a new century begins it is only we mortals who ring bells and fire off pistols.’
—— Thomas Mann, The Magic Mountain’
‘Ticking away the moments that make a dull day
You fritter and waste the hours in an offhand way.
… You are young and life is long and there is time to kill today
and then one day you find ten years have gone behind you.
… Every year is getting shorter, never seem to find the time.’
—— Pink Floyd, ‘Time’ from The Darker Side of the Moon
Men have always been curious about ‘time’. Our forefathers felt the changes in nature, saw the movement of the stars and of the sun, seasonal changes, night and day, and wisely attributed them to the Gods in charge of each specific environment.
The doubt about the essence of time as something that ‘moves’ or ‘flows’ or as something that ‘stays’ while we stroll through has been obscure for millennia. Even today the definition of time does not supply an answer to the question. The matter became even more complex with Hermann Minkowski’s theories on space (four-dimensional space-time as presented in his book Space and Time, 1907). The subsequent special theory of relativity by Albert Einstein and its various interpretations do not explain the essence of time. The idea of a curved space-time is fascinating but difficult to grasp. As for the relationship of the curved space-time with gravity, that is not an easy concept either, at least for me.
The master of Christianity’s philosopher Augustine, who thought a lot about time, gave up and said: ‘I know what it is, but I cannot explain it!’
(It’s interesting to notice that electricity also is known as a phenomenon, but is mysterious in its essence. But I am not qualified to elaborate any further on that.)
For centuries, the measurement of time was in fact the recording of the movement of the sun during the day and of the stars during the night. In relatively recent human history (300-400 BC) tools different from sundials were devised as water clocks and clepsydrae. The first mechanical clocks were built around 1400. The first ones were based on the isochronous pendulum then on the double pendulum and around 1700 by a spring-operated motor connected to an oscillating escapement.
When the Roman consul Messalla brought the first sundial to Rome from Catania (Sicily) and placed it in the centre of the Forum without any adaptation to negotiate the different latitude, the Romans used it for a whole century, unaware of or disregarding the structural error. Pliny the Elder commented with sarcasm, but disregard for the exact time is still today a peculiar trait of the Roman culture, where it is current habit, if not an institution, to be at least half an hour late. Romans have been smart to stamp punctuality as a somewhat negative habit, of more concern to plebeian society.
One peculiarity of Roman timekeeping is that the subdivision of the daylight time into twelve periods implied the subdivision of the night into twelve periods. Night ‘hours’ were longer or shorter than day ‘hours’ according to the season. Only on the equinox would the night and the day ‘hours’ be of the same duration.
The great Roman timekeeper after the year 10 BC was the obelisk in Campo Marzio erected by Augustus. Recent archaeological excavations brought to light the marble slabs with the hour signs traced into them, marking the time of the day as the shadow of the tip of the obelisk reached them. A monumental and celebratory sundial: on 23 September (the Emperor’s birthday) the shadow reached the Ara Paris which was the Giulia family mausoleum.
In the late imperial period in Rome, to own an ‘horologium’ was an important status symbol. Lucretius tells of a great water dock in the palace of the rich Trimalchio: a slave with a golden trumpet signalled every hour that passed so that his lord would know about the passing of life. The slave and the big water clock have long gone, but the idea of the clock as a status symbol is still strong, as evidenced by the likes of Girard-Perregaux advertisements.
Eventually, mechanical clocks became more sophisticated and accurate: the pendulum, the double pendulum. Harrison’s marine chronometer (H4 – the model that won the Board of Longitude prize presented in 1759 – could be accurate to less than 6/100 seconds per day).
After Harrison’s H4, the spring-loaded escapement chronometer became more and more accurate, mechanically sophisticated and smaller. The mechanical watch era was superseded in 1975 with the advent of commercial quartz watches.
Our post-Galilean culture privileges ‘measurement’. Everything must have a quantitative dimension; every dimension a consistent size. This has been the basic mandate for scientific research, certainly after Galileo, and quite possibly even long before his time.
Measurement was mainly related to the human body. The names of some of the early units are revealing, arm, foot, inch, palm, ‘passus’, History of science is the history of the measure of reality as the crucial tool for its knowledge. In some fields, knowledge and measure of reality conceptually overlap: to measure reality is to know reality and vice versa. To measure means to be able to know and to know means to be able to measure. Thus scientific culture privileges ‘quantification’ as a peculiar specific element to the understanding of any physical phenomenon. Transfer of this concept to problems outside of the domain of physics has been a consequence.
To be qualitative is a frequent comment that American researchers whip out to European peers – a well-known comment in the international scientific community. A quantitative attitude is in fact mandatory in the American scientific culture: if you do not have the ‘numbers’ your paper is dismissed as irrelevant, not supported by evidence, amateurish and thus usually disregarded. This was the situation as I remember it in the 1970s and 1980s when I was active in research and in close contact with many US institutions. I do not know if this is still the case today.
The need to have ‘numbers’ often induces manipulation of data or ‘shoehorning’ the interpretation of statistics to fit and support the assumed result. Sometimes the analytical method and field procedures are moulded by the need to achieve quantitative results beyond the scope of the research. The quantitative drive can sometimes betray the fundamental goal to obtain reliable, solid data for the scientific account of the real object of the study. Numbers can be solid evidence, but they can also subtly be bent to support an assumed result.
An interesting example of how numbers can be tricky can be seen in the works of Danish statistician Bjorn Lomborg (The Sceptical Environmentalist: Measuring the Real State of the World, 2001). With the same ‘numbers’ of other researchers through subtle manipulations or murky mathematical processing, of data, he reaches utterly different conclusions on the environmental reality. Lomborg’s work has been challenged by many authors who disclosed the mistakes and the manipulations. (Go to http://www.lomborg-errors.dk/examples.htm for more information on this.)
For centuries, quantitative measurement of phenomena has been rewarded with considerable success, thus strengthening the concept that ‘to measure means to know’ and that a physical phenomenon that cannot be measured or which has not been measured is, in fact, unknown. Strong doubt remains on what could have been achieved with holistic intuitive methods, a question strongly supported by the intuition of the atomic structure of matter which the Greek philosopher Democritus reached with an inductive mind-process 400 years BC, an intuition that has been dismissed as ‘fantasy’ for twenty centuries. The scientific method embraced after the Renaissance revolutionised research. The holistic intuitive way of thinking was abandoned, but nobody knows what we could have achieved if that had not happened.
A specific peculiarity of measurement and of measurement criteria is ‘conventionality’. All measurement units are ‘conventional’ and ‘relative’: until a few decades ago, the metre (a word that in Greek means ‘measure’) was the 40 millionth part of the earth meridian (according to Napoleon’s scientists) and the definition was re-established in 1983. The metre is the distance that light covers in a vacuum in 1/299,752,458 of a second; one degree Celsius is 1/100 of the thermal difference between water’s freezing point and water’s boiling point; the kilogram is the weight of one cubic decimetre of water at 4deg.C, where weight is the force applied to a body immersed into a gravitational field (on earth it is the result of gravitation and centrifugal force due to terrestrial rotation: thus weight varies with latitude and distance from the earth’s centre).
As for time, the natural frequency of the caesium atom was conventionally assumed as the new international time unit in 1967: the ‘second’ is the time needed to complete 9,192,631,770 cycles of the caesium atom resonance. This assumption supersedes the previous ‘rotational’ convention by which one second was the 86,400th part of the time needed for the earth to complete one rotation around its axis.
Interestingly, the international prototype of the kilogram (kept at the International Bureau of Weights and Measures in Paris) seems to have lost 50 micrograms in the last 100 years and the reason for the loss is unknown. The observed variation of the prototype has intensified the search for a new definition of the kilogram. It is accurate to state that any object in the universe that had a mass of 1 kg 100 years ago now has a mass of 1.000050 kg. This perspective is very disturbing (or pleasantly suggestive according to the point of view: destabilizing such a monument of certainty) and defeats the purpose of a standard unit of mass, since the standard should not change arbitrarily over time. The alternative is that we should accept the change and consistently negotiate the subsequent changed reality.
The effort of international institutions responsible for the definitions of measures is, wherever possible, to bring all the units to absolute values based on astronomical references (the speed of light in vacuum, earth rotation, gravity) or to physical invariants (like the natural resonance vibration of atoms). This effort does reduce conventional fickleness but does not solve conflicts between our subjectivity and its relationship with the historical and environmental context.
As for timekeeping standards, its measure is today entrusted to the relative constant resonance vibrations of a quartz crystal used as a capacitor interfering with an inductor. This technology reached the market with commercial quartz watches in 1975 with the catastrophically famous Black Watch by Sinclair. The product was a total failure. The chip could be ruined by static from your nylon shirt, nylon carpets or an air-conditioned room. This problem also affected the production facility, leading to a large number of failures before the watches even left the factory.
The result was that the display would freeze on one very bright digit, causing the batteries to overload (and occasionally explode) The accuracy of the quartz timing crystal was highly temperature-sensitive: the watch ran at different speeds in winter and summer.
The batteries had a life of just ten days, which meant that customers often received a Black Watch with dead batteries inside. The design of the circuitry and case made them very difficult to replace. The control panels frequently malfunctioned, making it impossible to turn the display on or, alternatively, impossible to turn it off – which again led to exploding batteries.
The kit was almost impossible for hobbyists to construct (and barely any easier for Sinclair’s hard-pressed workforce). Practical Wireless magazine advised readers to use two wooden clothes pegs, two drawing pins and a piece of insulated wire to work the batteries into position. You then had to spend another four days adjusting the trimmer to ensure that the watch was running at the right speed.
The casing was impossible to keep in one piece. It was made from a plastic which turned out to be unglue able, so the parts were designed to clip together. The clips didn’t work either and the problem was turned over to a subcontractor. Sinclair later (much later) received a small box on which was written, ‘We’ve solved the problem of the Black Watch!’ Inside was a Black Watch with a half-inch bolt driven through it.
From that horrible experience, present-day quartz watches have come a long way. They are very inexpensive and incredibly accurate (some of the commercial brands boast an accuracy within one second per year). All the original problems have been solved by design and technological innovations.
An ‘absolute’ accuracy (an audacious qualifier in the science of measurements) is granted by atomic clocks based on the vibration resonance of caesium atoms interfering with roper electromagnetic frequencies. This kind of accuracy responds to the needs of scientific measurements and is a vital tool for providing evidence to the theories of quantum physics and post-Einstein relativity positions, but it does not fill the gap between the measurement of time and the anthropological, cultural and biological perception that we have of it. The psycho-chronometry or chronobiology has yet to find its measurement means. The time we ‘live’ in fact and the perception we have of it is only vaguely related to the data available through timekeeping technologies. We can detect and assess sound, noise, weight, heat, textures and light with our senses, but a sense for ‘time’ is still a secret securely kept in our organism. It is a reasonable assumption that, since we have all the other senses, we also have an organic, built-in, sense of time.
It is not by chance that in our colloquial language time is qualified in a subjective, qualitative way: long, short, hard, slow, tormented, terrible, happy, far, close … In our everyday talk we seem to think about time as about something that ‘moves’: time goes by, runs, lags, doesn’t pass, stands still, etc.
This may be the consequence of the simple fact that timekeeping tools move or have moving components: clepsydrae, sundials, the hours and minutes hands, the vibrations of quartz or caesium. I could also be that the ‘movement’ of time is a logical consequence of the changes through which we perceive it.
A unique mind or logic transfer makes us think that time flows, drifts away, goes by, as if it were a fluid moving around us in the midst of which we stand still. Time would be better thought of as a huge, perfectly still ocean, in which we sail.
We sail: we move, we change, things around us change, move, grow, mature, season, lighten up or get dark, are born, live and die. We are born, live and die. Time is.
It’s not easy to think about a measure of time that ‘is’: the measure of time is the measure of the changes that we see or perceive. Changes can happen in the most diverse fields: physics, physiology, biology, biochemistry, astronomy, gravity, heat, culture, anthropology, society, politics, economy, geography, history and meteorology. Clearly each field is dominated by subjectivity, hence the reason for the many qualitative adjectives, which qualify ‘time’ for us and the perceptive assessment of it, more than its measure.
This is the important boundary: chronological measurement of time is different from its assessment through subjective perception. The search to supply subjective perception of time with quantitative parameters has not gone far and does not seem to be very popular in the present general field of human speculation. Biochronology and psycho-chronology are very specialized fields between psychology and biology, but they do not seem to have great communication channels with other interested disciplines.
The perception of time is still consigned to qualitative criteria. Can anything be done to get out of this segregation?
The fact that our perception of time and the current conventions for its measurement have marginal common ground is quite clear in all the literature. Some authors have also tried to explore a logarithmic time perception scale (Logtime) after the early attempts of Paul Janet (1823-1899), a professor of philosophy at the Sorbonne. Although his specific works on time are lost, they are quoted by William James (1842-1910) – often referred to as ‘the father of American psychology’ – in his monumental and ground-breaking work The Principles of Psychology (see Chapter XV, The perception of time).
The accepted observation that our time perception shrinks with our age suggests that time perception should be scaled as a logarithmic function: time appears to us to be slow (long) when we are young, and shorter as we grow older. We seem to assess and judge periods of time by relating them in some way to our age. One year for a ten-year-old boy is 10% of his life but only 5% of the life of a twenty-year-old man. So one more year in the life of the ten-year-old is felt like 10% of his life added to the experience whereas the twenty-year-old young man will feel to have added only 5% to his lived life. As we get older the faster we seem to age and the shorter years seem.
‘The longtime hypothesis is consistent with the widely accepted description of the perception of physical stimuli commonly referred to as the ‘Weber- Fechner law’. For time perception, clock time (calendar age) is the ‘stimulus’. Weber-Fechner has been found to be only an approximation over a limited stimulus range, and this would probably be the case for aging perception if objective measurements were possible’. (James Main Kenney, ‘Logtime: The subjective Scale of Life’, <http://ourworld.compuserve.com/ homepages/jmkenney>. In his essay, Kenney elaborates on the concept and supplies tables to scale one’s life according to the Longtime scale of life.)’
The literature on ‘time’ is vast and the philosophical debate is lively and proves the difficulties of the cognitive problem.
Basic definitions of ‘past’, future’ and ‘present’ are far from settled. William James in 1890 chose a ‘virtual’ category to define ‘present’ after the first use of the term by E.R. Clay: that of ‘specious present’. (He says: ‘the prototype of all conceived times is the specious present, the short duration of which we are immediately and incessantly sensible’.)
Starting from the classic Greek philosophers to Augustine and to the monuments of philosophical speculation, the efforts to understand what time is exactly have been incessant, but the results are still vague. Time sequences, simultaneity, time order, time perception and memory are still open issues.
Philosophy and logics developed a conceptual line of enquiry; neurobiology achieved some results. What is lacking is the connection and communication between the various disciplines, due to the segregation of domains and of the academic barriers so typical of the organisation of science and knowledge in our universities and scientific institutions.
The field of chronobiology should be explored by psychology and philosophy researchers working on the concept of time. It would also be useful for general medical practitioners to have an interest in the field.
All the activities directly or indirectly related to the human body and mind are interested in ‘lived time perception’: sports, recreation, work, education, communication, artistic expression, creative activities, food, social and public relations, sociology, management techniques, decision-making processes and methods, long-term planning, financial strategies …
Architectural and industrial design, urban design and town planning are all activities that interfere with ‘lived time’. Cities and houses contain and constrain time activities which interfere with our biological time.
Knowledge of biological time could be extremely useful while making financial decisions or strategic investments. Intergenerational and intercultural understanding could be greatly assisted by the knowledge of biological time.
Quite clearly, timekeeping machines based on astronomical references (rotational time) or on atomic resonance (quartz, caesium) cannot be abandoned because they are a fundamental structure for an organized society and because they are essential tools for research. Logtime is more related to humans and can be useful in many fields, but it is a hypothetical assumption supported by intuitive deductions, quite strong for its logical consistency with the Weber-Fechner theory.
Our personal daily matters and life choices, food, health, sport, social and family relationships could be better informed by our own ‘bio-time’, but we do not know anything yet about our inner organic clock for the subjective time perception of each individual.
The big question has not yet been answered: which specific elements of our complex metabolic processes or endocrine system change on an hourly or daily rate to supply the perception of our time to our brain?
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This site is an excellent starting point for many sites on the subject.