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 […]

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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.

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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

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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

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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

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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

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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

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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

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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

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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

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