11.3 Correspondence with Hale
231
On 23 July Kapteyn wrote back that he had renounced his intention to resign.
But he would never return to Mount Wilson, not in 1916, nor in any other
year.
The second theme concerns the conduct of scientific research. It started with
a remark by Hale that it was pointless to make catalogs for the sole purpose
of collecting data and not to gain more understanding. Kapteyn partly agreed
with this. Catalogs are certainly useful, but the problem was that they were
often made without any proper understanding of what they would be used for.
The random way in which data have been collected in astronomy is astonishing.
Take star positions, in a certain way the strong point because for over one hundred and fifty years such positions have been accumulating. Still, as soon as in
stellar research you want particular positions you are pretty sure not to find what
you want. So for instance data for the proper motions of stars fainter than 6 th
magnitude. So in many other instances. The trouble, I think, is that work was
undertaken without having in view any particular problem for the solution of
which the work is required. I know that many astronomers saw no other purpose
in the colossal undertakings of the Astron. Gesellsch. Zone Catalog 3 and the
Carte du Ciel than the providing of fixed points for eventual observations of
comets and minor planets. Of course I knew that you hated ‘catalogues’ just on
account of this, but I may have feared sometimes that your hate had led you too
far. I am extremely glad to find that it is not so. My studies have made of me
more and more of a statistician and for statistics we must have great masses of
data of course.
Hale and Kapteyn agreed that the ‘Art of Discovery’ was being neglected too
much. For Kapteyn this meant that people were insufficiently aware that they
had to work through induction; many proceeded too quickly on to deduction
and expected too much of it. ‘Induction’ was about taking stock of possible
general conclusions from a limited amount of data or assumptions and selecting
the most likely ones. ‘Deduction’ means drawing inevitable conclusions from
general rules and laws. Induction is ‘top-down’: from observations or measurements one finds empirically an underlying law. Deduction is ‘bottom-up’:
from a general principle or theory one derives specific consequences. It was said
that deduction is more suited to mathematics and induction to experimental
sciences, but these are generalizations.
Kapteyn took his Star Streams as an example. These are systematical motions
of the stars. The deductive approach would have been: ‘Take a wild guess,
deduce the consequences and see if they match the observations’. How long
3 The AGK was a German-led program to use meridian circles to determine the positions of stars up to
magnitude 9 with even greater accuracy than before.
231
On 23 July Kapteyn wrote back that he had renounced his intention to resign.
But he would never return to Mount Wilson, not in 1916, nor in any other
year.
The second theme concerns the conduct of scientific research. It started with
a remark by Hale that it was pointless to make catalogs for the sole purpose
of collecting data and not to gain more understanding. Kapteyn partly agreed
with this. Catalogs are certainly useful, but the problem was that they were
often made without any proper understanding of what they would be used for.
The random way in which data have been collected in astronomy is astonishing.
Take star positions, in a certain way the strong point because for over one hundred and fifty years such positions have been accumulating. Still, as soon as in
stellar research you want particular positions you are pretty sure not to find what
you want. So for instance data for the proper motions of stars fainter than 6 th
magnitude. So in many other instances. The trouble, I think, is that work was
undertaken without having in view any particular problem for the solution of
which the work is required. I know that many astronomers saw no other purpose
in the colossal undertakings of the Astron. Gesellsch. Zone Catalog 3 and the
Carte du Ciel than the providing of fixed points for eventual observations of
comets and minor planets. Of course I knew that you hated ‘catalogues’ just on
account of this, but I may have feared sometimes that your hate had led you too
far. I am extremely glad to find that it is not so. My studies have made of me
more and more of a statistician and for statistics we must have great masses of
data of course.
Hale and Kapteyn agreed that the ‘Art of Discovery’ was being neglected too
much. For Kapteyn this meant that people were insufficiently aware that they
had to work through induction; many proceeded too quickly on to deduction
and expected too much of it. ‘Induction’ was about taking stock of possible
general conclusions from a limited amount of data or assumptions and selecting
the most likely ones. ‘Deduction’ means drawing inevitable conclusions from
general rules and laws. Induction is ‘top-down’: from observations or measurements one finds empirically an underlying law. Deduction is ‘bottom-up’:
from a general principle or theory one derives specific consequences. It was said
that deduction is more suited to mathematics and induction to experimental
sciences, but these are generalizations.
Kapteyn took his Star Streams as an example. These are systematical motions
of the stars. The deductive approach would have been: ‘Take a wild guess,
deduce the consequences and see if they match the observations’. How long
3 The AGK was a German-led program to use meridian circles to determine the positions of stars up to
magnitude 9 with even greater accuracy than before.