Discursive writing demands more from a writer than fidelity to reason and logic; it also requires a fluency of expression that captures the nuances of his argumentation. While such fluency is achieved only by the commingling of many compositional elements, from grammar and punctuation to organization, it also greatly depends on the degree to which ideas and concepts are smoothly woven together. The most erudite scholar will fall short in arguing a thesis if he is unable to mirror the subtly of his thought in his writing. What guidelines might be useful in striving for such fluency?
To begin with, sentences must accurately capture the relations between and among ideas. The techniques to attain this objective are varied, but several of them are worth a closer examination. The link between an idea or concept and its implications, for example, can often effectively be conveyed by the use of demonstrative pronouns, such as this, that, the former, the latter, such, and so on. When properly employed to refer to an antecedent, such demonstratives powerfully link sentences and phrases, and hence, ideas. Participial phrases serve this function and also offer fuller explanations. Thus, when "Hume's philosophy" appears in once sentence and "Founded on human perception and experience" begins another, the more general concept is effortlessly defined.
Contradiction or disagreement are of equal importance to any argument, and these are most effectively expressed by the use of subordination, such as when one writes: "Although designed and built to withstand the concerted assault of modern artillery and aircraft, the Maginot Line proved incapable of protecting France from flanking probes of fast moving tank forces." Here, the relation between two related but conflating ideas - static defense versus dynamic attack - take but one sentence.