If you need an accessible version of this item please contact JSTOR User Support

Quark Quantum Numbers and the Problem of Microphysical Observation

K. S. Shrader-Frechette
Synthese
Vol. 50, No. 1, Philosophical Problems of Modern Physics, Part I: High-Energy Physics (Jan., 1982), pp. 125-145
Published by: Springer
Stable URL: http://www.jstor.org/stable/20115706
Page Count: 21
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
Quark Quantum Numbers and the Problem of Microphysical Observation
Preview not available

Abstract

The main question addressed in this essay is whether quarks have been observed in any sense and, if so, what might be meant by this use of the term, 'observation'. In the first (or introductory) section of the paper, I explain that well-known researchers are divided on the answers to these important questions. In the second section, I investigate microphysical observation in general. Here I argue that Wilson's analogy between observation by means of high-energy accelerators and observation by means of microscopes is misleading, for at least three reasons. Moreover, so long as high-energy "observation" is accomplished by means of spark or bubble chambers, then sentences about these observations do not meet Maxwell's criterion, that observation statements are quickly decidable. I argue, however, that this criterion is not a good norm for what is observable in high-energy physics, both because it would result in our describing a great many allegedly observed particle events as unobserved or theoretical, and because it fails to distinguish the reasons why some observation statements might not be quickly decidable. Most important, Maxwell's criterion fails because, contrary to Hanson's analysis, it presupposes that "seeing" does not involve both "seeing as" and "seeing that." With this background concerning what is meant by general microphysical observation, in the third section of the essay, I discuss what might be meant by a more particular type of observation, that of the quark via scattering events. I employ Feinberg's distinction concerning observation of manifest, versus existent, particles and claim that the alleged "indirect observation" of quarks as existent particles is really based on a retroductive inference. I explain which premise in the retroductive argument appears most open to the charge of being theoretical (in a damaging sense) and less substantiated by observation. In the fourth section of the essay, I discuss two different types of observation of quarks: detection of overt and hidden quark charm. Although this is only one illustration of alleged quark observation, I argue that the difference between the two types of observation of charm provides insight into which observations are less theoretical in a damaging sense. I claim that this case reveals, paradoxically, that an observation may be both more theory laden, but less theoretical in a damaging sense; that there is no real opposition between theory and observation (which is nothing new); that it might be wrong to think of an observation-theory continuum; and that who discovered charmed quarks is a function of what is meant by "observation." Finally, in the fifth and concluding section of the paper, I suggest that theoretical terms are essentially dynamic and that observations never really verify a theory. I close by suggesting why microphysical observations are becoming more theoretical, but not necessarily in a damaging sense. Both cosmological and microphysical observation demand that what is observed be seen in a very abstract way.

Page Thumbnails

  • Thumbnail: Page 
[125]
    [125]
  • Thumbnail: Page 
126
    126
  • Thumbnail: Page 
127
    127
  • Thumbnail: Page 
128
    128
  • Thumbnail: Page 
129
    129
  • Thumbnail: Page 
130
    130
  • Thumbnail: Page 
131
    131
  • Thumbnail: Page 
132
    132
  • Thumbnail: Page 
133
    133
  • Thumbnail: Page 
134
    134
  • Thumbnail: Page 
135
    135
  • Thumbnail: Page 
136
    136
  • Thumbnail: Page 
137
    137
  • Thumbnail: Page 
138
    138
  • Thumbnail: Page 
139
    139
  • Thumbnail: Page 
140
    140
  • Thumbnail: Page 
141
    141
  • Thumbnail: Page 
142
    142
  • Thumbnail: Page 
143
    143
  • Thumbnail: Page 
144
    144
  • Thumbnail: Page 
145
    145