David Armstrong (1926-) is an Australian philosopher who is a close contemporary of Place. Along with another Australian philosopher of the same generation, J. J. C. Smart (1920-), he has been responsible for much of the later development of the sort of identity theory that Place proposed.
Armstrong’s paper is divided into three unnumbered sections—pp. 31-32, 32-36, and 37-39. The main focus of our discussion will probably be on the second of these.
• In the first section, Armstrong comments on the role he thinks philosophy should be taken to have in dealing with these questions. You can find a brief statement of similar ideas in the last few sentences of the paper.
• The second section sketches the “causal theory” mentioned in the title:
• The basic idea is introduced via the examples of poisons and brittle objects as things that are “apt for causing certain effects” or “apt for being the effect of certain causes.”
• It is complicated by introducing the ideas of perceptions and beliefs. Notice how Armstrong attempts to characterize these things causally and think whether you take him to succeed.
• Beginning with the second column on p. 35, Armstrong concludes this discussion by pointing to two further problems for his causal theory and two advantages he sees in it. It is the last of these four topics that receives the bulk of his attention, and that discussion is something you should think through. (Franz Brentano, 1838-1917, probably had his greatest influence on later philosophers, but his views were also well-known among psychologists of his era.)
• The topic of Armstrong’s last section is roughly the same as the issue discussed in Place’s section V. How close do you think their views are about this issue? (The distinction between “primary” and “secondary” qualities dates to the 17th century. It is most closely associated with John Locke, 1632-1704, but it can found in earlier thinkers, too. In Locke’s way of making the distinction, primary qualities are true qualities of objects while their secondary qualities are powers these objects have to produce sensations in us.)