The title of this paper has reference to the well known remark which Whittaker has made about Einstein's Special Theory of Relativity in his book History of the Theories of Aether and Electricity. In the Chapter entitled ‘The Relativity Theory of Poincaré and Lorentz’ he writes as follows: “In the autumn of the same year… Einstein published a paper which set forth the relativity theory of Poincaré and Lorentz with some amplifications, and which attracted much attention… In this paper Einstein gave the modifications which must now be introduced into the formulae for aberration and the Doppler effect.” The question with which I am concerned in this paper is whether from a strictly empirical point of view Whittaker's assessment is correct.

In Chapter II of Word and Object, Quine presents and analyzes some of the philosophical difficulties found in the following situation: a linguist comes upon some jungle natives whose language is entirely unknown to him; the linguist then sets out to provide a translation of the jungle language into English. What the linguist would then be said to produce is a ‘radical translation’. Quine's thesis about radical translation is this: while, in a sense, translations can be produced, there are philosophical reasons why there can be no uniquely correct equivalence class of radical translations.

Although I have stated Quine's theme with respect to radical translation, it must be emphasized that even in this single chapter he is defending a far more general claim, i.e.:

The logical status of spatial and temporal congruence has been much debated. Recently the topic of debate has shifted from the alleged conventionality of congruence to the alleged eccentricity of congruence predicates. For example, espousing a point of view suggested to him by Nuel Belnap, Adolf Grünbaum has recently remarked that the predicate ‘x is (spatially) congruent to y’ deviates from the ‘classical account’ of the interrelations between the intensional and extensional components of the meaning of a predicate. By the classical account (hereafter CA), Grünbaum means the rather common view that the extension of a predicate is completely determined by its intension. Contrary to CA, Grünbaum maintains that “the fact that ‘being spatially congruent’ means sustaining the relation of spatial equality does not suffice at all to determine its extension uniquely in the class of spatial intervals.”