Many thinkers have provided analyses of the properties of consciousness, though not generally in the context of framing the putative properties in terms of their specific testability. To avoid the criticisms of untestability leveled against the 19th century phenomenologists, the goal of the present overview is to identify the specific properties of consciousness that provide the foothold of empirical testability in physiological terms. Of course, the properties of consciousness are, of their nature, subjective, but they may gain a measure of objectivity by consensus agreement on their validity. After proposing a working definition of consciousness and related terms, a representative range of proposals as to its properties is reviewed and elaborated into a larger set of testable properties of consciousness. Potential procedures for the specific implementation of relevant tests are then delineated.