iSoul In the beginning is reality.

Tag Archives: Time

the various senses of time; chronology, history, diachrony, synchrony

Ten meanings of time

Carlo Rovelli’s “Analysis of the Distinct Meanings of the Notion of “Time” in Different Physical Theories” (Il Nuovo Cimento B, Jan 1995, Vol 110, No 1, pp 81–93) describes ten distinct versions of the concept of time, which he arranges hierarchically. Here are excerpts from his article:

We find ten distinct versions of the concept of time, all used in the natural sciences, characterized by different properties, or attributes, ascribed to time. We propose a general terminology to express these differences. p.81

… our aim is to emphasize the general fact that a single, pure and sacred notion of “Time” does not exist in physics. p.82

The real line is a traditional metaphor for the idea of time. Time is frequently represented by a variable t in R. The structure of R corresponds to an ensemble of attributes that we naturally associate to the notion of time. These are the following:
a) The existence of a topology on the set of the time instants, namely the existence of a notion of two time instants being close to each other, and the characteristic “one dimensionality” of time;
b) The existence of a metric. Namely the possibility of stating that two distinct time intervals are equal in magnitude. We denote this possibility as metricity of time.
c) The existence of an ordering relation between time instants. Namely, the possibility of distinguishing the past direction from the future direction;
d) The existence of a preferred time instant, namely the present, the “now”. p.83

In the natural language, when we use the concept of time we generally assume that time is one-dimensional, metrical, external, spatially global, temporally global, unique, directed, that it implies a present, and that it allows memory and expectations. The concept of time used in Newtonian physics is one-dimensional, metrical, external, spatially global, temporally global, unique, but it is not directed and it does not have a present. In thermodynamics, time has the additional property of being directed. Proper time along world line in general relativity is one-dimensional, metrical, temporally global but it is not external, not spatially global, not unique; on the other side, the time determined by a matter clock is one-dimensional, metrical, but not temporally global, an so on. p.87

… the notion of present, of the “now” is completely absent from the description of the world in physical terms. This notion of time can be described by the structure of an affine line A. p.88

… our list does not include the possibility of considering a non-metric but directional notion of time. p.89

Table I. [without the fourth column]

Time concept Attributes Example
time of natural language memory brain
time with a present present biology
thermodynamical time directional thermodynamics
Newtonian time uniqueness Newton mechanics
special relativistic time being external special relativity
cosmological time space global proper time in cosmology
proper time time global world line proper time
clock time metricity clocks in general relativity
parameter time 1-dimensional coordinate time
no time none quantum gravity

… our hypothesis concerning time is that the concepts of time with more attributes are higher-level concepts that have no meaning at lower levels. p.91

If this hypothesis is correct, then we should deduce from it that most features of time are genuinely meaningless for general systems. p.91

… we suggest that the very notion of time, with any minimal characterization, is likely to disappear in a consistent theory that includes relativistic quantum-gravitational systems. p.91

… the concept of time, with all its attributes, is not a fundamental concept in nature, but rather that time is a progressively more specialized concept that makes sense only for progressively more special systems. p.92

Sun clocks


The Sun is like a clock.

Sun and sundial (click for animation)

Hours correspond to the Sun’s motion.

24-hour clock (for animation click here)

This 24-hour clock is a representation of looking south. The sun rises on the left and sets on the right. At noon the sun and the clock appear straight up.

But we’re accustomed to maps that have east on the right, which corresponds to looking north so the sun rises on the right and sets on the left.

Are clockwise clocks backwards?

It seems that automated clock numbering was based on sundials. The article here notes that the shadow on a vertical sundial moves clockwise on horizontal and north-facing sundials.

Counter-clockwise 12-hour clock

To match the motion of the sun with east on the right and west on the left would require a clock that is a 24-hour clock and moves counter-clockwise.

Click here to see a 24-hour counter-clockwise clock, Florence Cathedral.

Flow of motion

Note: previous posts on this topic are here and here.

Motion flows. That is, there is always motion independent of us. We can also make standard motions that are effectively independent of us. They are called clocks. They can be used as standards of comparison to measure other motions.

Clocks are needed for synchronous measurement of motion. They can also be used for asynchronous measurement of motion, but simpler devices can be used for that, too. For example, a circular clock provides a standard angular motion to compare synchronously with another motion. The marked angles or circumferential lengths could be used for asynchronous measurement. So could protractors and rigid rods.

Clocks can have various units of measure. A population clock estimates current population growth (or its decline). Mechanical clocks use an escapement to count periods of standard motion. A water clock measures the flow of water in units of volume. An hourglass measures the flow of sand. A clock can be made from any regular motion that can be associated with or marked in units.

Thus clocks, or “flowkeeping devices,” are independent, standard movements to compare with other motions, either synchronously or asynchronously.

From common experience we know there are three dimensions of motion. These three dimensions of motion can be measured synchronously or asynchronously. Synchronous measurements measure time; asynchronous measurements measure space.

For every motion one can associate six measurements: three synchronous measurements and three asynchronous measurements. That is, there are three dimensions of time and three dimensions of space.

To associate motion with position or location one must sum or integrate motions. One takes an arbitrary starting point, an origin, and integrates motion in different dimensions to construct a coordinate system for positions. Asynchronous integration leads to spatial coordinates. Synchronous integration leads to temporal coordinates.

Change flows

Change happens. In fact, everything in the physical universe is changing. Note that refers to things in the universe, not the universe itself. Whether or not the universe itself changes is another question.

There are as many kinds of physical change as there types of energy: kinetic, thermal, chemical, electrical, electrochemical, electromagnetic, sound, and nuclear change (potential energy being related to kinetic energy). How do we measure change? We could simply compare one change with another of the same type.

But how do we measure change in general? Is there a framework in which all changes can be placed? The simplest answer is to adopt a single aspect of change, the beginning and ending of a standard change, as the unit of change. The question then is how many of these units of change does it take to measure a particular change (the measurand)?

A number of units of change is a rate of change. A standard rate of change would allow one aspect of every change to be measured. It would also enable a framework in which all changes could be placed if the standard rate of change generates a dimension of change that continues indefinitely.

What change would work well as a standard? It should have a regular rate of change. It should also have a clear beginning and ending, that is, it should be cyclic. Each cycle would constitute one unit of change.

The ancient standard was the cycle of days with the sundial as a convenient way to measure change. Over the centuries the movement of water, the burning of a candle, mechanisms of gears and weights, the cycle of a pendulum, and oscillations of quartz have been used as a standard rate of change.

Notice that I have avoided the words “time” and “clock”. There was no need for them. We could call a clock a change-measuring instrument. And time? That’s just another word for the rate of change measured by a clock.

Does time flow? If that means that change is always happening, then yes. But if the flow of time is supposed to be something intrinsic to the universe, that’s the assertion that the universe itself is changing. There is no need to go there to answer a simple question about change.

Variations on a clock

The U.S. National Debt Clock shows several ‘clocks’ that tick off dollars at a constant rate. The answer to “what time is it?” could be given in dollars.

The Census Bureau has a population clock that estimates the present population for the U.S. or the world. The U.S. has a net gain in population of one person every 12 seconds. The answer to “what time is it?” could be given as a number of people.

The current price of a stock in a stock market ticker is a kind of clock. Or a trader might be interested in the time until the market closes, which would be a countdown clock. The countdown to launch a rocket or celebrate the new year are famous countdown clocks.

With GPS trackers anyone can have a distance ‘clock’ with them. “What time is it?” could be translated into “how far have you gone?” Metres, miles, or some other distance would answer the question. A sprint might last a certain ‘time’ measured by distance.

A clock with a second hand of 0.16 metre would sweep out one metre in one minute. Time could be converted to distance with this ratio. Ten o’clock would mean 600 metres swept out since beginning the day.

There is no need to measure ongoing change with only clocks of hours, minutes, and seconds. Many other units can be used.

Time and memory

Is it possible to reverse time? Yes, in a sense. It is possible to reverse thermodynamic time by a local decrease in entropy. Cooling down, metabolism, and memory are examples of decreases in entropy.

Memory may be described as an information model: it compresses experience for storage. The information in memory is not all that happened; something was lost or not perceived.

As memory grows, it is necessary to do maintenance like that done with computer systems, such as defragmenting isolated memories and consolidating them into coherent storage. This, too, may decrease entropy. It is also necessary to review memory, to restore weak memories. This remembering, this return to the past, is a form of reversing time.

Time for us is memory. Without memory, there is no time–we are like children focused on the here and now.

Weekly and annual cycles of remembrance renew our memories and help integrate them into an existing framework. The cycle of the week is the cycle of creation and rest. The cycle of the year is the cycle of reviewing the history of God’s people. Other cycles give us a rhythm for life–cycles of the tides, of the school year, of national holidays.

The Greek word chronos describes these regular cycles, whereas the word kairos describes a progression. Chronos is measurable, predictable, cyclic time. Kairos is experienced time, which flows and grows in unpredictable ways. The experiences of kairos are turned into the cycles of chronos by memory.

Centers of time measurement

The ancient center of time measurement was the earth, and this is still used in everyday life. The changing positions of the sun and moon relative to the earth make a convenient clock. In this sense, geocentric time makes sense. But the movements of planets are difficult to use in this way; their retrograde movements require ad hoc modifications to a geocentric system.

The proposal to switch to a sun-centered time system was met with resistance but its advantages eventually won out, with Newton’s laws ending the issue. The greater comprehensiveness of heliocentric time (heliochronic system) over geocentric time (geochronic system) proved to be decisive. Nevertheless, the everyday terms noon, morning, afternoon, etc. are still used, showing the naturalness of a geochronic system.

In the 20th century, the atomic clock was invented, which uses an electronic transition frequency of the electromagnetic spectrum of atoms (the signal electrons in atoms emit when they change energy level). This might be called a “phochronic” (light-time) standard. The positions of celestial bodies are not used with this system of time. It is an acentric time standard.

If accuracy is the most important factor, then a phochronic system is best. But it is not surprising that the “24/7” way of life arose since this acentric system was implemented. Time is less and less connected with the rhythms of the sun, the week, the seasons, etc. If the latter are the most important, then the geochronic system is best since it fits well with these rhythms, which are still an important part of the cycles of life.

Theory selection and time

There are several criteria commonly used to select the best scientific theory, including consistency, confirmation, and comprehensiveness.  We discuss two criteria in particular:

(1)  “Avoid metaphysics.”  Modern science has a long history of avoiding metaphysics.  Science was often contrasted with the wrangling of metaphysicians.  While some metaphysical assumptions/presuppositions may be inevitable, a theory is preferred that has fewer metaphysical assumptions.  “Don’t make metaphysical assumptions if possible, and if unavoidable, make them as benign as possible.”  This incorporates “Occam’s razor” which says that entities should not be multiplied beyond necessity.

Naturalism or methodological naturalism is often considered a requirement for a scientific theory but the real requirement is the avoidance of metaphysics.  Naturalism does avoid some metaphysical assumptions but it has its own metaphysical assumptions.  A naturalistic theory should not be considered free of metaphysics, rather, its particular metaphysics should be considered along with everything else when selecting a theory.

(2)  “Take the metaphysical middle way.”  When the making of metaphysical assumptions cannot be avoided, a theory is preferred that has metaphysical assumptions in the middle of the range of metaphysical assumptions that have historically been employed.  “Avoid metaphysical extremes.”  Follow something like a golden mean or an intermediate metaphysical position.

Example:  historical time

  • An ancient and primitive conception of time is that it is cyclic, that history repeats. As the seasons and celestial positions repeat so does history.  Cf. also Nietzsche’s Eternal Return.
  • A modern and abstract conception of time is that of an open time line, that history is a linear sequence of events projected onto an open-ended geometric line. Such a line has no definite endpoints or is infinite.  Relativistic time lines may be curved but the idea of an open-ended sequence remains.
  • An intermediate conception is that historical time is a closed time line, with beginning and ending points. This is the Judeo-Christian conception of time. It is like the cyclic conception in that it consists of one cycle and in some ways the ending recapitulates the beginning. It is also like the time line conception in that it is a linear sequence of events.2007
  • That which is “natural” conforms to these two principles.  It has few metaphysical assumptions and what assumptions it has are middle-of-the-road so it is easy to accept.



For evolution time and change are critical.  If there is insufficient time for evolution, it fails.  If time and change don’t explain everything, evolution fails.  The backbone of evolution is its dating methods.  Time is the key to evolution.

But time is not a critical variable for creationists.  Creation is basically the same as it was in the beginning.  Variations and catastrophes are secondary to the constancy of creation.  After scientists understand what doesn’t change, then they can fit change into that framework.

Creationists should not follow evolutionists in thinking that time and chronology are the key to science.  They are not.  Invariance is the key to science and it always has been.  That’s why real science studies physical laws and their consequences.

June 2014

The limits of secular science

“Secularity” is often distinguised as “what is secular” compared with “secularism” which means the promotion or the expansion of secularity.  The problem is not what is secular but an expansive meaning to what is secular.

Historically, “secular” meant of an age or of this world (as opposed to the age or world to come) or civil or worldly (as opposed to spiritual or religious). One conclusion is that matters to do with the world before mankind existed should not be considered secular. Just like the age to come, that is a matter for religion. So “secular science” should not concern itself with matters of ultimate origins, nor of a “deep time” that is said to occur before humanity existed.

Since vast ages of time before the advent of man were accepted into science in the 19th century, science is no longer genuinely secular. It has crossed the line into the dimension beyond this age, the age of human life in this world.

Creation science also crosses this line in a different way, following the revelation of the creation week. Those who want a secular science will have to drop deep time or creation and only reference this world, the world of human life.

So a genuinely secular science would be a limited science that could not explain many things such as how humanity got here, how the earth got here, or how starlight got here. It would be a limited science.

It would still be possible for a secular science to be influenced by non-secular perspectives as long as it doesn’t stray beyond its borders. There would be a limited, but level field for science to take place.

August 2012