Computing Reviews 30: 55-57, 1989. Publication of the book under review: Cambridge, Mass.: MIT Press, 1988.

The main part of this dissertation is the development, in several stages, of logical formalisms for expressing issues related to situations involving several items that react with one another over a period of time. This field of interest is illustrated in terms of scenarios involving rolling and colliding billiard balls. A later section discusses causation as an additional issue of these formalisms.

To this reviewer the decisive issue in this presentation is the starting premise--the assumption that significant insight into the events taking place when solid bodies, such as billiard balls, move about can be obtained solely by calculations with truth values, that is, by reasoning. This essential assumption becomes evident on page 9, where it is suggested that, in dealing with moving objects, 'precise numerical information (such as the precise distance between two billiard balls) is unnecessary and unavailable'.

It seems to this reviewer astounding, indeed appalling, that at this time in history, 300 years after Newton, such a view of motions and mechanics can be entertained. How can anyone dealing at all seriously with time and motion be unaware that the motions of the heavenly bodies, including their encounters in eclipses, are calculated very successfully as a matter of astronomical routine, and that the motions of aircraft are being calculated continuously in airport control systems, to mention just two examples. How can anyone present one hundred pages of formalism in order to arrive at a non-solution of the problem solved with high efficiency by Newtonian mechanics? For despite the author's claims about its efficiency, what emerges after these hundred pages is a non-solution.

Causation, the second issue taken up by the author, fares no better than mechanics. The author quotes seven lines from Bertrand Russell's discussion of cause, which establishes quite clearly that causes have no place in physics and astronomy, but then joins several other authors who quote Russell without grasping his message. It occurs to none of these authors that meaningful talk of causes, like meaningful talk of anything else, is a matter of context and situation. A typical context and situation would be that of a serviceman being called in to fix a broken TV set. The cause here might be a defective line cord, for example. Spelled out in more detail, the context is that of a person dealing with a thing involving several issues or parts, which are intended by the person to serve a particular function. The situation is that the thing fails in its intended function, and we are then entitled to ask for the cause of the failure.

It is meaningful to ask why something fails to function according to our intent. To ask why something functions properly makes no sense, since the circumstances that lead to the present situation of the world are beyond enumeration. In the book under review this latter notion gives rise to what is called the frame problem. The reader is misled by this euphemism into expecting that it will be solved. It will not.

It is a sad reflection on the state of computer science that the present work can not only be published as a book, but be accepted as a Ph.D. dissertation by Yale University. It has no merit.