Philosophy of research refers to the development of knowledge adopted by researchers in their research (Saunders, Lewis, & Thornhill, 2009). In other words, it is the theory that guided the researcher in conducting the procedure of research design, research strategy, questionnaire design and sampling (Malhotra, 2009). It is very important to have a clear understanding of the research philosophy so that we can examine the assumptions about how we see the world, contained in the research philosophy we choose, knowing whether they are appropriate or not (Saunders, Lewis, & Thornhill, 2009). According to Saunders, Lewis, and Thornhill (2009), three main ways of thinking about philosophy of research are examined: ontology, epistemology, and axiology. Each of them carries significant differences that will impact how we view research procedures. Ontology “is concerned with the nature of reality,” while epistemology “is concerned with what constitutes acceptable knowledge in a field of study, and axiology “studies value judgments” (Saunders, Lewis, & Thornhill, 2009, p110 , p112, p116). This study aims to create some "facts" starting from the objective assessments made by the subjects. Therefore, epistemology will be chosen for this study as a way of thinking about research philosophy. More specifically, epistemology also contains three philosophical positions: positivism, realism, and interpretivism (Saunders, Lewis, & Thornhill, 2009). The positivist position usually advocates the investigation or study of an observable social reality and the final production might be “law-like generalizations similar to those produced by physical and natural scientists” (Remenyi et al. cited in Saunders, Lewis and Thornhill , 2009, p113) . It is effective to generate a research strategy to collect credible data that comes from observable reality, thus contributing to the development of hypotheses (Saunders, Lewis, & Thornhill, 2009). In this study, we aim to explore the credible and measurable outcomes of individuals in order to understand the influence of surprise on viral marketing via social media in perspective of message characteristics. Therefore, the philosophy of positivism will be adopted in this study to collect credible data from subjects to produce some “law-like generalizations”. However, it is always difficult to decide whether interpretivism should be applied to conduct a more in-depth analysis related to subjects' attitudes in order to improve accuracy. More complicated, such a dilemma would often lead to reflection on realism, which is divided into direct realism and critical realism (Saunders, Lewis and Thornhill, 2009).