ABSTRACT
In this inaugural lecture I have chosen to explore a specific (though admittedly a broad) theme, rather than to issue a manifesto expounding the nature or justifying the academic existence of my subject. What kind of subject I take it to be will, I hope, be implicit in what I say about my theme. But, lest my capacity for intellectual innuendo be unequal to my intentions I begin with some brief indications of a more explicit character.
