Evidence of Absence

Evidence of absence is evidence of any kind that suggests something is missing or that it does not exist. A simple example of evidence of absence: A baker never fails to put finished pies on her windowsill, so if there is no pie on the windowsill, then no finished pies exist. This can be formulated as modus tollens in propositional logic: P implies Q, but Q is false, therefore P is false.

Per the traditional aphorism, "absence of evidence is not evidence of absence", positive evidence of this kind is distinct from a lack of evidence or ignorance of that which should have been found already, had it existed. In this regard Irving Copi writes:

In some circumstances it can be safely assumed that if a certain event had occurred, evidence of it could be discovered by qualified investigators. In such circumstances it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its non-occurrence.

Read more about Evidence Of Absence:  Overview, "You Can't Prove A Negative", Existence of God

Famous quotes containing the words evidence of, evidence and/or absence:

    Generally there is no consistent evidence of significant differences in school achievement between children of working and nonworking mothers, but differences that do appear are often related to maternal satisfaction with her chosen role, and the quality of substitute care.
    Ruth E. Zambrana, U.S. researcher, M. Hurst, and R.L. Hite. “The Working Mother in Contemporary Perspectives: A Review of Literature,” Pediatrics (December 1979)

    No doubt Jews are most obnoxious creatures. Any competent historian or psychoanalyst can bring a mass of incontrovertible evidence to prove that it would have been better for the world if the Jews had never existed. But I, as an Irishman, can, with patriotic relish, demonstrate the same of the English. Also of the Irish.... We all live in glass houses. Is it wise to throw stones at the Jews? Is it wise to throw stones at all?
    George Bernard Shaw (1856–1950)

    Meanwhile, if the fear of falling into error sets up a mistrust of Science, which in the absence of such scruples gets on with the work itself, and actually cognizes something, it is hard to see why we should not turn round and mistrust this very mistrust.... What calls itself fear of error reveals itself rather as fear of the truth.
    Georg Wilhelm Friedrich Hegel (1770–1831)