In Alfred North Whitehead's phrase, the whole of the European philosophical tradition is but "a series of footnotes to Plato." It is no surprise, then, that one can find the seeds of the discourse regarding the relationship of thought to language in Plato's works. One can find countless examples in the Socratic dialogues in which Socrates initiates discussion of a philosophical concept by asking first about the meaning of the concept itself. The question "What do we mean by justice?" is the initial attempt to distinguish words from the ideas behind them, and the process of philosophical inquiry is a rhetorical exercise. Therefore, the nature of the relationship of word to thought must first be understood as a relationship of word to other words.
If words can be directly yoked to ideas, the implication is that people can use words as a tool to understand the foundational aspects of humanity: desires, needs, wants, emotions. If words and ideas are necessarily yoked, then language and thought have a profound connection. Language can be used to mold thought, language can be used to describe thought accurately, and language can be trusted as a reliable map of the human psyche. This position, taken to its extreme, was expressed by the French grammarian Condillac in the preface to his Grammaire:
I regard grammar as the first part of the art of thought. In order to discover the principles of language it is necessary to observe how we think. It is necessary to look for these principles in the very analysis of thought... Now, the analysis of thought is completely accomplished in discourse. This is what makes me think of languages as so many methods of analysis (Condillac, as cited in Gilson 1).
If, however, thought and language are not yoked, or are only tenuously yoked, then the implication is that human understanding of the world, when in the framework of language, can only be a partial understanding. In fact, if the link between...