ABSTRACT
The author analyses the concept of sensation. This analysis is important, for philosophers, especially the Cartesian theorists, have a tendency to use 'sensations', 'sense-data', and 'sensible qualities' interchangeably. A sensation is that which a normal human being naturally has when his body stands in a certain kind of relationship to different kinds of physical objects. Consider the following example: Besides being invalid and having false premises, the argument is untenable on the grounds that it wrongly supposes that we infer the existence of material objects from sense-data. In the argument from illusion, or hallucination, sense-data were posited to explain hallucinations and sensory illusions. But in the next argument, the role of these theoretical entities is not merely to explain sensory illusion or hallucination but also to provide solid foundations for all our empirical knowledge. As the author might put it the concept of perception is on a more elementary or less technical level than that of sense-impression.
