RE: ATM - How Do We Know Things

["Mel Bartels" <mbartels@efn.org>]

>>> There are several ways we can know things to be true:

You are too modest and leave out psychic ways of knowing.  For the right
price, I will devine the wave rating of the mirror, from a considerable
distance, merely by pressing a bag of cerium oxide to my forehead.  Call
1-900-FOUCAULT.

Appeal to authority is a very sensible means to knowledge.  Authority is
not just a person but also a body or collection of observations and
conclusions: hopefully tested hypotheses.  It is also a shorthand quick
way of knowing, relieving us from the burden of retesting everything for
ourselves.

How and what we believe appears to be emotionally based, and often for
surprising reasons.  I direct those interested to Michael Shermer's
books.

The Foucault test, according to authority, can be used to make a good
mirror, but is often wildly inaccurate in amateur hands.  My
observations is that this is a fairly accurate statement.  However, we
cannot generalize to the specific, and can never say much about a
particular mirror or individual. So when someone says that someone else
overstated a Foucault test result, there is nothing that we can really
say, except to handle the emotional or social side of the situation.

And in the end, mirror making as Suiter has said, is a social contract
with others and with oneself.  The experience at the eyepiece is
ultimately subjective.  That's why there is and will always be endless
debate on the classic questions of refractors vs reflectors and
obstruction effects ad naseum.

So our job as mentors and advisers is to offer words of wisdom that are
most likely to lead to satisfaction, subjectively of course, at the
eyepiece.  That's why I recommend the Ronchi followed by the star test,
but certainly for many, the Foucault test can fulfill this role nicely,
and I also recommend it.

It would be sad if both original parties to this discussion came away
with the wrong conclusion:  that one side attacked 'my' mirror and
called it 'not very good', when it likely will perform tremendously well
at the eyepiece.  After all, that's really what was being said by the
statement of "1/22.7 wave error". The attempt to leverage this statement
into a discussion of the Foucault test is fine, but it should not be
confused with the social side or emotional side of the statement.

Mel Bartels