Final answer:
Positivism is the theoretical orientation that emphasized the verifiability of observation and it supports the realist view that scientific knowledge can be empirically tested and confirmed as true.
Step-by-step explanation:
The theoretical orientation that emphasized the verifiability of observation is Positivism. Positivism is associated with the belief that information derived from sensory experience, interpreted through reason and logic, forms the exclusive source of all certain knowledge. Positivism asserts that only scientific knowledge is the true form of knowledge. It supports a realist perspective, where scientific theories provide true explanations because their predictions can be empirically tested and verified. This stands in contrast to theoretical orientations like Behaviorism, which focus on the observable behaviors rather than internal states, and Existentialism, which emphasizes individual existence and personal experience. Positivism underlies the methodologies used in the natural sciences and has influenced approaches to research in sociology, differentiating between quantitative (positivist) and qualitative (antipositivist) methodologies.