ABSTRACT
Criteria of truth and rational justification are normative features of language; conditions for the possibility of meaningful verbal communication. The physical phenomena observed by Eratosthenes and the rudimentary apparatus which he used to measure the globe's circumference with tolerable accuracy were as accessible in later millennia as they were in the pre-Christian era. Revolutionising theories make sense as innovatory contributions to an understanding of the realities asserted by traditions of inquiry, even if they are incommensurate with the logic of the explanations they supersede. Connections are frequently drawn between critical thinking, personal autonomy, freedom and democracy by contributors to the present 'thinking skills debate' as well as in the more sustained manner of precursors iike Mill, Dewey and Popper. Word-meaning accumulates and is gradually integrated within the various social institutions of language. Human consciousness of the world, including conceptions of time, space and causation have differed quite radically according to the access to a cultural repertoire afforded by particular social, institutional and linguistic forms.
