Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983. This dissertation documents John Wilkins' contributions to the science of language analysis. I analyze his Essay towards a Real Character and a Philosophical Language (1668) concentrating on his lexicographic and lexicological achievements and the scientific apparatus that he uses to organize his classification schemes. I show how the Wilkins project must be considered a legitimate contribution to the practice of lexicography: with his friend William Lloyd he constructed a dictionary which anticipated later trends of lexicography and surpassed his contemporaries (e.g. general inclusion of ordinary words; multiple senses of single lexical items; fixed combinations--idioms, set collocations; systematic and impartial presentation of definitions). Though this dictionary has been largely ignored in the scholarship of the history of lexicography, I demonstrate the need to reappraise the accepted tradition of English lexicography. I have compared entries from the dictionaries of Blount (1656), Kersey (1708), Bailey (1721) and Johnson with the alphabetical dictionary appended to the Essay. In the sections on the lexicological practice of Wilkins I document the semantic organization underlying the classification tables based on my analysis of the text which reveals that organization; these tables can be seen as an application of a structural analysis of the lexical items representing concepts Wilkins deemed as universal. The arrangement of the tables follows a binary and hierarchical formula. The most important aspect that I have found regarding the organization of the tables is Wilkins use of what we would call distinctive features. In order to better appreciate the Wilkins system, I compare relevant portions of classificatory and semantic work done preceding and succeeding 1668 with the principles I have deduced from Wilkins' text. I look at works of classification (Comenius; Dornseiff; Hallig-von Wartburg; Roget), works of structural/componential analysis (Coseriu; Katz-Fodor; Nida) and a design for a dictionary (Apresyan-Melcuk-Zolkovsky). I claim that Wilkins' work is organized by systematically (with lapses) applied principles. These principles, which I have deduced from my analysis of the Essay, anticipate much of what we regard as modern linguistic-semantic theory. U of I Only Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs