How Science Resists the Philosophical Concept that Perception is Flawed

In the traditional theory, which still is the prevailing one, there were alleged to exist inherent defects in perception and observation as means of knowledge, in reference to the subjectmatter they furnish. This material, in the older notion, is inherently so particular, so contingent and variable, that by no possible means can it contribute to knowledge; it can result only in opinion, mere belief. But in modern science, there are only practical defects in the senses, certain limitations of vision, for example, that have to be corrected and supplemented by various devices, such as the use of the lens. Every insufficiency of observation is an instigation to invent some new instrument which will make good the defect, or it is a stimulus to devising indirect means, such as mathematical calculations, by which the limitations of sense will be circumvented. The counterpart of this change is one in the conception of thought and its relation to knowing. It was earlier assumed that higher knowledge must be supplied by pure thought j pure because apart from experience, since the latter involves the senses. Now, it is taken for granted that thought, while indispensable to knowledge of natural existence, can never in itself provide that knowledge. Observation is indispensable both to provide authentic materials to work upon and to test and verify the conclusions reached by theoretical considerations.

John Dewey, The Quest for Certainty: A Study of the Relation of Knowledge and Action (1929)

• knowledge
• perception