The Two Faces Of Zero
Introduction
Our culturally-based assumptions about numbers have a long and varied
history. We have constructed "rules" of mathematics, based on
knowledge passed from generation to generation. Among these is the way we
think of zero.
We commonly think of zero as a single number. In fact, it has 2
distinct meanings:
- It is used as an ordinal value between -1 and 1 as in the set { -1,
0, 1 }
- It is also a measure of quantity which may be nothing at all, as in
the null set { }
The ordinal use of zero is a one-dimensional number.
The null view of zero is zero-dimensional.
We typically treat zero in calculations as a hybrid of these 2 meanings.
While these assumptions and rules work most of the time, there are cases
where they fail. This is not to say that mathematics fails, simply our
assumptions about the way it works.
It is our convention to treat zero as a real number half-way between -1
and 1. This is the case where it is used as an ordinal value, but is not
necessarily correct when it is used as a quantity.
Our conventions can be maintained most of the time, but there are
several cases where our assumptions falter, such as:
- Division by zero
- 00 (0^0 or zero raised to the 0th power)
- Planck's Constant h=E/v, when E=0
- Infinities in physics
These give different results if we assume that, for the purposes of
multiplying or dividing a quantity, zero is a null { } or nothing
rather than a real number between -1 and 1 { 0 }. That is, if it treated
as the absence, rather than the presence of a number.
Cultural Considerations
There are 2 different versions of zero and there are different types of
infinities.
In Western culture we treat both representations of zero as "0"
and all infinities interchangeably as "∞".
We often don't even have words in our vocabulary to differentiate between
them.
We are culturally conditioned from an early age to demand a result from
every equation and to "know" that 1/0 = "infinity" and
that infinity+1=infinity.
The difference in views of zero didn't really matter too much until the
mathematics of Planck or Einstein's times. It rarely seemed to matter much
in Newton's day, when many of our current "rules" were made up
or formalised from a variety of Greek, Indian, Arabic and other
traditions.
{ 0 } as zero worked for centuries, although there was always some
discomfort about zero and the whole "infinity" thing due to
inconsistent results and odd exceptions to rules.
Below we look at the consequences of viewing zero as the absence of any
number. That is, as "null" or as an empty set { }, rather than
as the set of a single number { 0 }. We compare the results of modern
physics with our conventional views. These examples are often,
almost by definition, at the very limits and at boundary conditions as
this is where the differences arise.
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