Title: "Our Word is Our Weapon"
Description: What are political thinkers doing with their words when they write a text, engage in a debate, or give a speech? We propose a "computational political theory", pairing recent breakthroughs in computational linguistics with the hermeneutic practices of intellectual history, as a set of tools for mapping out the political-discursive fields within which ideas circulate. We begin by showing, via a series of historical case studies, how a particular class of computational-linguistic algorithms called word embeddings are able to capture subtle differences in how authors employ certain contested terms (liberty, freedom, sovereignty, etc.) by explicitly modeling both the words and the contexts they're used in across a corpus of texts. We then demonstrate how the results of these embedding models can shed light on important questions in the history of political thought, by performing two in-depth studies of the origins and trajectories of Marxism from the 19th to the 20th century. In the first study, we use these models to trace the construction of Marx's thought out of the raw intellectual materials of 18th and early-19th century philosophy.

We combine a new, comprehensive corpus of Marx's complete works from 1835 to 1883 ($N > 1200$) with a large sample ($N = 250$) of prominent 18th and early-19th century texts to measure conceptual distance between Marx's works and various schools of 19th-century thought (political economists, socialists, and Hegelian philosophers) over time. Two key breaks emerge in Marx's writings: (a) they become less Hegelian as he is exposed to Paris' brand of working-class-oriented socialism between 1843 and 1845, then (b) become more focused on issues of political economy over the remainder of his life in London, from 1849 onwards. Our second study turns from the origins to the illocutionary impacts of Marx's published works, assessing his influence on the broader socialist discourse of the 19th century using a corpus of \textit{post}-1850 socialist texts ($N = 200$). We find that Marx's semantic trajectory is mirrored, with a lag, by changes in the semantic trajectory of European socialist thought.

This discourse shifts away from moralistic and Hegelian themes and towards a more positivistic political-economic vocabulary, especially after Marx's rise to public prominence in the wake of the 1871 Paris Commune. Our findings thus trace out, within the computationally-inferred ideological field of 19th-century socialist thought, how Marx's unique blend of German philosophy, French socialism, and British political economy defeated would-be competitors and established his thought as the default language of European socialism by the time of Engels' death in 1895. The dissertation thus demonstrates the utility of modern context-sensitive language models as tools for historical research, providing a framework for their use in developing, testing, and revising our understandings of key questions in the history of political thought.