Divine Neutrality

Exponential Growth

June 8th, 2009

Living cells multiply. Their number grows exponentially. The more there are the faster they increase. An exponentially growing population has a doubling time: the time it takes for the population to double. Having a doubling time is a characteristic of exponential growth. In the time it takes each individual cell to divide into two cells, the whole population of cells doubles. The population doubles because each of its members doubles.

An amount of money invested at a compounded interest rate of, say, 7%/year, grows exponentially. It has a doubling time. After 10 years the return on the investment will be as much as the original investment itself. The original investment will have doubled in value. Each of the dollars in it will have doubled. In the next ten years the money will have doubled again - to four times the original investment. The rate of growth, r, is related to the doubing time, T, by the simple formula: rT = Ln 2 = 0.7 (approx).

The motion diagram shows exponential growth through four doubling times at the rate of 7% per second. The exponentially growing brown bar doubles in size every 10 seconds. The green bar increases in size linearly at 7% per second. Clicking on GO starts the growth. Clicking on STOP freezes time. You can assess the doubling by stopping time at 10 seconds (first doubling), 20 seconds (two doublings)  and 30 seconds (three doublings) etc.

Things that do not grow exponentially are the distance the train carries you away from the train station or the amount of coffee in the cup you are pouring. These increase only linearly with time. The increase has a rate of growth but no characteristic doubling time. The time for the second doubling is not the same as that for the first doubling. Rather it is twice as long. The third doubling takes four times as long. So, in linear growth, no single period of time characterizes a doubling.

No matter what mathematics governs its increase, any physical quantity must eventually stop increasing. Nothing goes on increasing forever. Eventually the mathematics of growth fails to describe the phenomenon. Growth is never sustainable.

See Can growth be sustainable?

The Equation

June 7th, 2009

hangrBrdJennifer says, with enthusiasm, “I love equations.”

What’s to love?

An equation is is a statement that says ‘this equals that’. It’s hard to imagine, from that raw and basic idea, that something called an equation could be of any use. Whether ‘this equals that’ or not seems a matter of little consequence!

But, in fact, we know that to state what things are equal can have powerful consequences.

Newton’s law - that the net force on something causes it to accelerate - is a matter of things being equal. Force = mass multiplied by acceleration. This law of nature governs an extraordinary panoply of phenomena: the solar system, the entire NASA program of space exploration, the working of engines, the nature of energy and thus of pressure and of temperature and thus our understanding of weather. It underlies thinking in engineering, geology, chemistry, biology, and, of course, physics. All from ‘this = that’.

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Innate Goodness

April 25th, 2009

mywayMy dear friend, Connie, wrote: “The paragraph below is quoted from … an interview with Jack Kornfield, one of the founders of Spirit Rock in Woodacre. ”

In “Civilisation and its Discontents”, Freud says, “Culture has to call up every possible reinforcement in order to erect barriers against the aggressive instincts of men…Its ideal command to love one’s neighbor as oneself is really justified by the fact that nothing is so completely at variance with original human nature as this.” From a Buddhist perspective, nothing is so at variance with our original nature as the “aggressive instincts” Freud describes. In fact, aggression, hatred, and greed are seen as based in delusion and covering over our innate goodness.

‘Original human nature’, ‘innate goodness’. Is there meaning attached to these phrases?

How measure what is ‘human nature’? How can one know what is at the core of all human activity? Is there a single ‘nature’ which drives the behavior of all humans? Is there any empirical foundation for the idea that ‘aggressive instincts (are) original human nature’ or for the opposite view that ‘aggression, hatred, and greed are … covering over our innate goodness.’?

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