Re: Fact -- a useless concept

On 4 Apr, 04:53, Ivar Ylvisaker <ylvis...@xxxxxxxxxxx> wrote:
Devils Advocaat wrote:
On 2 Apr, 18:04, Ivar Ylvisaker <ylvis...@xxxxxxxxxxx> wrote:
Ernest Major wrote:
Do you also object to describing the existence of atoms (and electrons,
and protons, and neutrons) as a fact; to describing the cause of disease
by microorganisms (and viruses) as a fact; to describing the earth as
(roughly) spherical, and the solar system as heliocentric as facts; to
describing the source of energy emitted by the sun as due to nuclear
fusion as a fact, to describing the Yellowstone caldera as due to a very
large volcanic eruption as a fact, etc. If not, on what grounds do you
make the distinction.
Yes.

Atoms, viruses, etc. are elements of theories.   In the terminology of
the philosophy of science, they are "theoretical."

If atoms are simply theoretical elements, then how come we can capture
images of them?

http://www.sfc.fr/material/hrst.mit.edu/hrs/materials/public/STM_intr...

And here is an image of a molecule of naphthalocyanine

http://www.gizmag.com/go/7920/picture/37092/

If viruses are simply theoretical elements, then how come we can also
capture images of them?

http://www.lib.uiowa.edu/Hardin/md/cdc/8160.html

We are not observing the atoms, molecule, and viruses directly.  What we
are observing are images of these objects made with with Scanning
Tunneling Microscopes (STM) and a transmission electron microscope
(TEM).  It is these images that are our facts, our data.  We can't see
the targets themselves.

I don't wish to split hairs but the image of the viruses that I
provided a link to was not created using an STM but an eletron
microscope.

And truth be known, there are high resolution optical microscopes
using nanoapertures that can be used to observe objects in the size
range of 8 to 250 nanometres.

But given your reasoning that "these images are our facts", you could
argue that using any system that creates an image denies direct
observation of the target object.

Which would in turn mean even the use of the human eye and the optical
cortex of the brain, denies us direct observation of the target
object, as again all we have is the image and not the object.


These microscopes are complex electronic devices.  They don't work at
all like our eyes.  It is these devices that are the links between the
images that are our data and the target objects.  Our knowledge of the
targets depends the images and on our understanding of the theories of
operation of these devices.  If we discovered that our understanding of
the theories behind these devices was flawed or incomplete -- and that
is certainly possible -- the images wouldn't change but our
understanding of the targets would.  The targets are theoretical because
our understanding of them depends on our understanding of the theories
behind the imaging equipment.

I am afraid I have to disagree, one doesn't need to understand the
theories behind any device in order to make use of it, look at the
number of people who make use of cars, computers, televisions,
microwave cookers, mobile phones and many other modern devices, who
know nothing about how these devices actually work, and yet have no
trouble using them.

To say that something is theoretical does not mean that the existence of
that something in some form is questioned.  And we don't need a picture
of an object to recognize that a theory incorporating that object is
useful.  The structure of DNA was discovered using X-ray diffraction
images, which don't look at all like DNA.  The existence of atoms was
based on theories needed to explain observed phenomena and not on any
picture of what atoms looked like.

Ivar- Hide quoted text -

- Show quoted text -

.

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