Question

Why is 2 + 2 =4?

Answer 1

say you had two rocks and your friend gave you two more rocks than you would have four rocks. if you added three you would have five

Answer 2

The simple answer is that, in everyday mathematics, in number base
systems higher than ?4,? 2 + 2 = 4 because it is defined as such.
Based on the definitions of the number ?2?, the number ?4?, and the
mathematical operation of addition, the answer is always the same. It
is at the basis of all number theory and other branches of
mathematics.

Simply put, if you take a pile of objects that we designate as
consisting of ?2? objects, and place it with another identical pile,
the count of the resulting pile of objects is equal to what we label
as the number ?4.?

Of course, there are other number systems and other ways of doing math
where that definition is not used, but they don?t generally produce
very useful results for everyday applications.

You can find a longer explanation at:
http://www.mathmojo.com/interestinglessons/why%20do2plus2equal4/why%20do2plus2equal4.html,
but it says generally the same thing.

It may surprise you to learn that an entire book, Principia
Mathematica, (the one by Whitehead and Russell, 1910-1913, not the one
by Sir Isaac Newton in 1687) devotes several hundred pages to deriving
an explanation of just why 2 + 2 = 4 (actually, as I recall, it was 1
+ 1 = 2).

I don?t recommend that you pick up a copy of this 2,000-page,
three-volume set, since it consists almost entirely of equations.

You can find some excellent discussions about the nature of
mathematical proofs and in particular some 3,000 logic and set theory
proofs at:
http://us.metamath.org/mpegif/mmset.html

In particular, you can find links to a 122-level ?proof? of why 2 + 2 = 4 at:
http://us.metamath.org/mpegif/mmset.html#trivia

A complete proof, such as the one presented in Principia Mathematica,
involves 1,789 sub-theorems consisting of 19,731 individual steps.

As some others have already commented, the question about quantum
mechanics only applies to extremely small events at and below the
atomic level. The mathematics involved in solving questions in quantum
mechanics seldom even involves addition. In the simplest sense, as I
once heard an old friend, John Van Vleck, Nobel Laureate Physics,
1977, say, you should always think of any question involving quantum
mechanics as being a question of probabilities. In that sense, in
quantum mechanics 2 + 2 never = 4 with any certainty.

You will find a more extensive, but still reasonably accessible,
introduction to quantum mechanics and mathematics at:
http://www.math.rutgers.edu/~oldstein/quote.html

One thing to keep in mind is that when you start getting into the
details of advanced physics then you must switch languages. The reason
things don?t seem to make sense at the atomic and sub-atomic levels is
that non-physicists are forced to discuss things in English or some
other language, which leads to what appear to be contradictions. In
reality, you can only discuss such things in mathematics, which is why
you will find most scientists very reluctant to talk about their work
with non-scientists.

Think about it this way. You would never use chemistry notation to
show someone how to bake a cake. In the same way, you simply can?t
explain most advanced physics concepts in English or any spoken
language; the best you can do is summarize, simplify, and generalize ?
the language simply won?t support detailed explanations without
resulting in apparent paradoxes or contradictions.

I hope you consider this an adequate answer for the price.


http://answers.google.com/answers/threadview/id/330537.html <---This is the guy I copied and pasted the answer from ... lol (Answered By: siliconsamurai-ga)

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