"Asking why" is an important foundation of inquiry and fundamental to the development of reasoning skills and learning. Despite this, and despite the relentless and often disruptive nature of innovations in information and communications technology (ICT), sophisticated tools that directly support this basic act of learning appear to be undeveloped, not yet recognized, or in the very early stages of development. "Why is this so?" To this question, there is no single satisfactory answer; instead, numerous plausible explanations and related questions arise. After learning something, however, "explaining why" can be revealing of a person's understanding (or lack of it). What then differentiates "explanation" from "information"; and, "explanatory" from "descriptive" content? What ICT scaffolding might support inquiry instigated by "why"-questioning? What is the role of reflective practice in inquiry-based learning? These and other questions have emerged from this investigation and underscore that "why"-questions often propagate further questions and are a catalyst for cognitive engagement and dialogue. This paper reports on a multi-disciplinary, theoretical investigation with a view to informing the broad discourse on e-learning by identifying a specific frontier for design and development of e-learning tools. Probing why reveals that versatile and ambiguous semantics present the core challenge--asking, learning, knowing, understanding, and explaining "why." [For the complete proceedings, "Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on Cognition and Exploratory Learning in Digital Age (CELDA) (Madrid, Spain, October 19-21, 2012)," see ED542606.]