The Absolute and Its Measurement: William Thomson on Temperature

Abstract

In this paper we give a full account of the work of William Thomson (Lord Kelvin) on absolute temperature, which to this day provides the theoretical underpinnings for the most rigorous measurements of temperature. When Thomson fashioned his concepts of 'absolute' temperature, his main concern was to make the definition of temperature independent of the properties of particular thermometric substances (rather than to count temperature from an absolute zero). He tried out a succession of definitions based on the thermodynamics of ideal heat engines; most notably, in 1854 he gave the ratio of two temperatures as the ratio of quantities of heat taken in and given out at those temperatures in a Carnot cycle. But there were difficulties with using such definitions for experimental work, since it was not possible even to approximate an ideal Carnot engine in reality. More generally, it is not trivial to connect an abstract concept with concrete operations in order to make physical measurements possible. In the end, Thomson argued that an ideal gas thermometer would indicate his absolute temperature, and that the deviation of actual gas thermometers from the ideal could be estimated by means of the JouleThomson effect. However, the measurement of the Joule-Thomson effect itself required measurements of temperature, so there was a problem of circularity.

The nature of the physical and the meaning of physicalism

“…On the existence of an "absolute" scale of temperature I remain silent. See Chang & Yi (2005). 21 This supplies a ready objection to a naive extensionalist representational theory of measurement.…”

Calibration: A Conceptual Framework Applied to Scientific Practices Which Investigate Natural Phenomena by Means of Standardized Instruments

“…A relatively important corpus of socio-historical studies dedicated to the local conception and realization of new instrument devices, which, at a point or another of their developments, are led to mention calibration, fall within this second perspective. In this vein, we can mention, for instance, Bourget, Licoppe and Sibum (2002), Chang (2004), Chang and Yi (2005), Heering (2005), Licoppe (1996), Livengood (2009), Schickore (2007), Sibum (1995. In many of the studies of this corpus, however, calibration is not the central topic: it is considered incidentally, or among other, equally or most important issues (for example, the theoretical principles on which the explanation of the instrument rests).…”

Reduction of Thermodynamics: A Few Problems

“…For there is a sense of generic/specific in each pair. Historically, TD-temperature 1 was chosen among infinitely many absolute temperatures in such a way that TD-temperature 2 as measured on the Celsius scale could approximate it (Ter Harr and Wergeland 1966, 20-23;Chang and Yi 2002). On the other hand, when we try to find SM-temperature 2 in a SM system, we use our physical intuition based on SM-temperature 1 to think hard to find what the manifestation of this abstract concept in this particular system could be.…”