The discrepancy between what is asserted in the economic theory and what really occurs in the economic world always embarrasses economic theorists and prompts debates on economic theorizing among economic theorists and methodologists. The traditional way to deal with this problem is to raise the issue of realism versus theory by focusing on the concern of unrealistic assumptions in economic theories. This paper, by using a case study from international trade theory, argues that, contrary to traditional wisdom, economic theorists’application of unrealistic assumptions in economic theorizing is not a vice with respect to the empirical tradition; it rather figures in economic theory-building in just the same way as does physicist’s procedure of condition-control in theory-building in experimental physics. According to this view, unrealistic assumptions are introduced into theories to act as controlling devices to safeguard theoretical models against disturbing influences produced by other, less relevant or less important causal factors and to ensure that the main targeted phenomena can be elicited from these shielded theoretical models. The conclusions derived from these shielded theoretical models are the so-called abstract causal laws (or abstract capacity claims). They are the main targets of economic theorists. From this perspective, inaccuracy as a characteristic of economic theories is not surprising. This paper further argues that, economic theorists, by so doing and coupling with their practices of executing theory-concretization, can show us a strong case that what they have done in their economic theorizing or model-manipulation represents an attempt to provide more complete causal accounts of the economic phenomena in question.