Viewing the process of lexical acquisition as a joint activity, this study proposes an alternative to the dominant approaches to lexical acquisition. Based on longitudinal data, it discusses the various types of conversational exchanges in which new words are introduced in everyday interaction. By exploring the full range of explicit lexical introductions, this study also points out the limitations of many experimental studies. In particular, the types of introduction often examined in experimental studies—namely, adult-initiated labeling, anchoring, and explanation—account for only 8% of all the explicit introductions identified in this study. Other types of explicit introductions, such as repairs, are examined in the context of introducing verbs, adverbs, adjectives, and prepositions. I suggest that by using experiments to determine if there is a correlation between the rate of uptake and the type of introduction, it is possible to explain why words belonging to certain grammatical categories are learned before others.

Advances in the synthetic control of semiconductor nanostructures and material properties offers many opportunities to enable new technologies. This is especially true for advances in the areas of photovoltaics, light emitting diodes, photodetectors, transistors, miniaturized lasers, and thermoelectrics. In this work, I demonstrate the synthesis and properties of several novel nanoscale morphologies composed of copper sulfide, cadmium sulfide, and halide perovskite, which can be useful for these applications. Here, I demonstrate the first synthesis of Cu2S-CdS core-shell nanowires by reverse cation exchange, and I explore the evolution of the epitaxial interface during the cation exchange. In addition, I demonstrate the synthesis and photovoltaic properties of core-shell CdS-Cu2S nanorod arrays with power conversion efficiencies approaching 4%. I also demonstrate the first bottom-up synthesis of CH3NH3PbBr3 nanorod arrays and the first example of morphology-conserving anion exchange to CH3NH3PbI3. As a demonstration of this, I created and characterized the first halide perovskite nanorod array light emitting diodes. Furthermore, using the first example of ultrathin halide perovskites, I demonstrate the unexpected changes in the structural and optical properties of layered halide perovskites as they approach ultrathin thicknesses. Finally, I synthesized the first example of all-inorganic, lead-free perovskite CsSnI3, which is shown to possess strong photoluminescence at 1.3 eV, metallic electrical conductivity, and ultralow thermal conductivity. These research directions all contribute towards the ultimate goal of providing new nanostructured materials to enable new technologies and innovations, which might also lead to new energy generating and energy saving applications.

The "scope" of Pyrrhonian Skepticism refers to the extent to which Skeptics bear epistemic commitments. There are two respects in which the debate between unmitigated and mitigated interpretations of Skepticism is significant. First, there is the philosophical question of which version of Pyrrhonism is more coherent and compelling when considered on its own merits. Second, there is the historical question of which sort of interpretation accurately characterizes Pyrrhonism itself, as it is presented in the works of Sextus Empiricus.

My own arguments proceed accordingly. On the philosophical front, I argue (primarily in Chapters 2 and 3) that when the force of the Skeptical modes is fully understood, they are unmitigated in scope. On the historical side, I argue (primarily in Chapters 1 and 4) that an unmitigated interpretation of Pyrrhonism is consistent with the Sextan corpus. Throughout, my ultimate aim is to present a vision of unmitigated skepticism that is, if not an expression of the historical reality of Pyrrhonism, at least a direct descendant of it.

The central argument concerns the Five Modes of Agrippa, which are widely regarded as comprising the most powerful argument of Pyrrhonian Skepticism: the "Pyrrhonian Problematic." The intuitive force of the Problematic lies in its generality. It threatens to cast into doubt every claim that can be advanced on every subject. According to the standard interpretation, the Problematic achieves this by constituting a declarative argument that consists of appealing premises and the conclusion that epistemic justification is impossible.

I argue that this interpretation fails to capture the intuitive force of the Problematic in two ways: First, it is a mistake to interpret the scope of the Problematic as being narrowly restricted to the concept of epistemic justification. Second, and more importantly, it is a mistake to assume that the Problematic is an argument in the first place. Understanding its full potential requires that we instead interpret the Problematic procedurally, as a set of instructions that the Skeptic implements in engaging dialectically with an interlocutor’s claims.