Many stories of the development of political theory in the Anglo-American world in the 20th C could be told to involve many different actors, events, and ideas. This dissertation tells a story that centers on the development of modern liberalism by locating within it the development of the ideas of Charles Taylor (1931-). Taylor's writings on the study of human behavior, the relationship between selfhood and morality, the contemporary relevance of German Romantic philosophy, and the need for advocating multiculturalism and democracy in politics have captured the major debates internal to these fields and have earned him wide recognition as a leading philosopher of our times. By making clear how his arguments about human agency and knowledge form the basis of how social practices should be understood for the strong values they embody, this project shows how the connections between his philosophy of social sciences and his writings on morality and politics constitute a highly salient defense of interpretivism and humanist liberalism for our times. This dissertation brings to light a range of problems, themes, and arguments that mark an "interpretive turn" in philosophy and across the sciences that helped to shape political theory in the Anglo-American context in the 20th C, and explains the ways in which some of those 20th C concerns continue to be of especial importance for political theorists today. Since the demise of logical positivism and the rise of critical forms of thought that render suspect the means for rational debate over normative claims or for discourse without domination, the central project of political theory in the 20th C has been to grapple with what makes for satisfactory ways of understanding social actions and meanings. The last century saw key shifts in ways of thinking where previous philosophical concerns about the possibility, nature, and foundations of knowledge, and preoccupations with the structure of language and the analysis of meaning gave way to greater interest in and new controversies over questions about interpretation: the role of interpretation in human life, the kinds of knowledge to which interpretation gives rise, what interpretative practices presuppose about the knowing subject and the subject matter, and how to judge between interpretive successes and failures. Such questions not only augured epistemological problems for the human sciences, but doubts about established notions of science, truth, and objectivity also bespoke of impediments to comprehensive reflection across cultural, traditional, or linguistic lines, and to the pursuit of rational debate over values. Perceived failures within philosophy combined with lessons drawn from the hermeneutic tradition as well as developments in the interpretive disciplines of historiography, philosophy of science, jurisprudence, cultural studies, and literary criticism served to challenge all forms of foundationalism - epistemological, moral, and cultural, and have redrawn traditional boundaries of knowledge across disciplinary lines. As we grapple with how best to understand human practices and social meanings, political theorists also face a variety of reasons to doubt what intelligible loci exists for understanding texts, what means we have for rational debate over substantive goods, or whether normativity without domination is ever possible.This dissertation shows how Taylor is a major figure in this historical and philosophical context by explaining how his arguments continue to capture the major internal debates in each of the areas of philosophy of social sciences, moral philosophy, and political theory today. His defense of anti-naturalism pertains to the major issues in the debate over naturalism and the use of scientific techniques in the human sciences. By further probing on what grounds anti-naturalism is right - if it is - Taylor's arguments pierce through much of the controversy within moral philosophy over the grounds for normative theory, refashioning a version of moral realism that learns from each the emotivist, rhetorical, and historicist alternatives, while eschewing their pitfalls. By taking an interpretive approach to both theory and practice, Taylor's humanist liberalism also attempts to break the impasses within political theory between moral philosophers, critical theorists, and intellectual historians. The view of politics that arises from Taylor's philosophy of social sciences is neither one derived from moral philosophy, nor one focused solely on structures or power. Nor is the practice of political theory meant to be an apolitical, antiquarian exercise in uncovering the meanings of past texts. Taylor's is a vision of politics that urges recognizing, grasping, and debating the intersubjective meanings that make up collective life, a view that enables social and political criticism while circumventing the strongest arguments both about the practical contradictions of deconstruction, and those against moral realism. As a project on the history of contemporary political thought that begins with a study of Taylor's earliest influences, this dissertation contributes to the growing interest among scholars today to examine the development of analytic philosophy as a matter of history, which reverses long-standing assumptions of an ineluctable development of the purportedly essential features of analytic philosophy in the 20th C. Tracing the historical roots and philosophical contours of Taylor's interpretivism and humanist liberalism in the arguments of Berlin and Hampshire against the intellectual context of positivism and modern empiricism, moreover, shows the development of an alternative strand of thinking within the analytic tradition that strongly opposes what is regularly thought of as "analytic" theory today, especially in the liberal tradition. Reading Taylor as a humanist liberal, therefore, provides a corrective to the erroneous interpretations of his political theory as opposing liberalism that still persists due to the many commentators who remain in the long shadow of the liberal-communitarian debate of the `80s. And calling attention to this alternative interpretive and humanist liberal mode of inquiry that despite undergoing changes, nonetheless persisted through the rise and fall of logical positivism thereby unseats the commonplace notion that Anglo-American political theory post-WWII lay moribund until Rawls reinvigorated it in the 1970s. This dissertation shows how Taylor's engagements in the flight from positivism in the philosophy of social sciences, his interventions in the rise of post-foundationalist challenges to modern moral philosophy, and his confrontations with the problem of justification for liberal political theories all serve to define the distinct yet related implications of a turn to interpretation in the triplicate areas of knowledge, values, and politics. Taylor's interpretivism shows us that defending anti-naturalism in the human sciences after the fall of logical empiricism and the demise of positivism requires a sophisticated, post-linguistic turn, positive case for moral realism that is based on an interpretive understanding of human beings necessarily and always engaged in social practices. Taylor's particular brand of interpretivism, moreover, opens up the possibility, after the demise of logical positivism, for a philosophy of social sciences to be more than strictly a knowledge enterprise but itself a critique and a politics. Taylor makes it possible to bring moral argument back in to the study of politics without choosing between a fixed foundation for knowledge and the practical contradictions of deconstructivism, by reconciling what appear to be incommensurable opposites. By rejecting the autonomy of ethics and combining ethical individualism with ontological communitarianism, Taylor has reformulated what seems antithetical about dichotomies and has shown how rejecting representationalist theories of knowing, objectivist explanations of human conduct, and essentialist notions of the good need not entail a radical "epistemology without a subject", render theory as mere conversation, or values simply as whatever happens to be preferred. The following pages, therefore, serve not only to clarify Taylor's positions as they relate to current debates in political theory, but also to narrate the multiple and competing intellectual traditions from which contemporary political theories in the Anglo-American context have arisen by locating Taylor's place in it. This project makes a sustained inquiry into the relationship between political theory and the broader movements in philosophy in the 20th C that have called the former into question that simultaneously bridges the study of modern liberal theories with key issues of justification and meta-methodology in the philosophy of social sciences.