Sense Data

In the philosophy of perception, the theory of sense data was a popular view held in the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A.J. Ayer, and G.E. Moore. Sense data are supposedly mind-dependent objects whose existence and properties are known directly to us in perception. They are supposed to be unanalyzed experiences inside the mind, which appear to subsequent more advanced mental operations exactly as they are. Sense data are often placed in a time and/or causality series such that they occur after the potential unreliability of our perceptual systems, but before the possibility of errors during higher-level conceptual analysis, so are incorrigible. They are thus distinct from the 'real' objects in the world outside the mind, about whose existence and properties we often can be mistaken.

Talk of sense-data has since been largely replaced by talk of the closely related qualia. The formulation the given is also closely related. None of these terms has a single coherent and widely agreed-upon definition, so their exact relationships are unclear. One of the greatest troubling aspects to 20th century theories of sense data is its unclear rubric nature.