Evidence of absence

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Evidence of absence is evidence of any kind that suggests something is missing or that it does not exist. What counts as evidence of absence has been a subject of debate between scientists and philosophers. It is often distinguished from absence of evidence.

Contents

Overview

An exhaustive inspection of the attic for vermin can provide evidence of absence, but any sign of mice will always suffice to the contrary. Attic-roof-DE-0a.jpg
An exhaustive inspection of the attic for vermin can provide evidence of absence, but any sign of mice will always suffice to the contrary.

Evidence of absence and absence of evidence are similar but distinct concepts. This distinction is captured in the aphorism "Absence of evidence is not evidence of absence." This antimetabole is often attributed to Martin Rees or Carl Sagan, but a version appeared as early as 1888 in a writing by William Wright. [1] In Sagan's words, the expression is a critique of the "impatience with ambiguity" exhibited by appeals to ignorance. [2] Despite what the expression may seem to imply, a lack of evidence can be informative. For example, when testing a new drug, if no harmful effects are observed then this suggests that the drug is safe. [3] This is because, if the drug were harmful, evidence of that fact can be expected to turn up during testing. The expectation of evidence makes its absence significant. [4]

As the previous example shows, the difference between evidence that something is absent (e.g., an observation that suggests there were no dragons here today) and simple absence of evidence (e.g., no careful research has been done) can be nuanced. Indeed, scientists will often debate whether an experiment's result should be considered evidence of absence, or if it remains absence of evidence. The debate regards whether the experiment would have detected the phenomenon of interest if it were there. [5]

The argument from ignorance for "absence of evidence" is not necessarily fallacious, for example, that a potentially life-saving new drug poses no long-term health risk unless proved otherwise. On the other hand, were such an argument to rely imprudently on the lack of research to promote its conclusion, it would be considered an informal fallacy whereas the former can be a persuasive way to shift the burden of proof in an argument or debate. [6]

Science

In carefully designed scientific experiments, null results can be interpreted as evidence of absence. [7] Whether the scientific community will accept a null result as evidence of absence depends on many factors, including the detection power of the applied methods, the confidence of the inference, as well as confirmation bias within the community. For instance in amnesia studies, the absence of behavior indicative of memory is sometimes interpreted as the absence of the memory trace; however, certain researchers consider this interpretation flawed as the memory impairment may be temporary due to deficits in recall. [8] Alternatively, the memory trace be latent and demonstrable via its indirect effects on new learning. [9] [10] Michael Davis, researcher at Emory University, argues that complete erasure can only be confidently inferred if all of the biological events that occurred when the memory was formed revert to their original status. [11] Davis contends that because making these measurements in a complex organism is implausible, the concept of complete memory erasure (what he deems "strong form of forgetting") is not useful scientifically. [11]

Law

In many legal systems, a lack of evidence for a defendant's guilt is sufficient for acquittal. This is because of the presumption of innocence and the belief that it is worse to convict an innocent person than to let a guilty one go free. [3]

On the other hand, the absence of evidence in the defendant's favor (e.g. an alibi) can make their guilt seem more likely. A jury can be persuaded to convict because of "evidentiary lacunae", or a lack of evidence they expect to hear. [12]

Proving a negative

A negative claim is a colloquialism for an affirmative claim that asserts the non-existence or exclusion of something. [13] Proofs of negative claims are common in mathematics. Such claims include Euclid's theorem that there is no largest prime number, and Arrow's impossibility theorem. There can be multiple claims within a debate, nevertheless, whoever makes a claim usually carries the burden of proof regardless of positive or negative content in the claim. [14] [15]

A negative claim may or may not exist as a counterpoint to a previous claim. A proof of impossibility or an evidence of absence argument are typical methods to fulfill the burden of proof for a negative claim. [13] [16]

Philosopher Steven Hales argues that typically one can logically be as confident with the negation of an affirmation. Hales says that if one's standards of certainty leads them to say "there is never 'proof' of non-existence", then they must also say that "there is never 'proof' of existence either". Hales argues that there are many cases where we may be able to prove something does not exist with as much certainty as proving something does exist. [13] : 109–112  A similar position is taken by philosopher Stephen Law who highlights that rather than focusing on the existence of "proof", a better question would be whether there is any reasonable doubt for existence or non-existence. [17]

See also

Related Research Articles

An irrelevant conclusion, also known as ignoratio elenchi or missing the point, is the informal fallacy of presenting an argument that may or may not be logically valid and sound, but fails to address the issue in question. It falls into the broad class of relevance fallacies.

<span class="mw-page-title-main">Argument from ignorance</span> Informal fallacy

Argument from ignorance, also known as appeal to ignorance, is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false or a proposition is false because it has not yet been proven true. This represents a type of false dichotomy in that it excludes the possibility that there may have been an insufficient investigation to prove that the proposition is either true or false. It also does not allow for the possibility that the answer is unknowable, only knowable in the future, or neither completely true nor completely false. In debates, appealing to ignorance is sometimes an attempt to shift the burden of proof. The term was likely coined by philosopher John Locke in the late 17th century.

<span class="mw-page-title-main">Fallacy</span> Argument that uses faulty reasoning

A fallacy, is the use of invalid or otherwise faulty reasoning in the construction of an argument that may appear to be well-reasoned if unnoticed. The term was introduced in the Western intellectual tradition by the Aristotelian De Sophisticis Elenchis.

In scientific research, the null hypothesis is the claim that the effect being studied does not exist. Note that the term "effect" here is not meant to imply a causative relationship.

The association fallacy is a formal logical fallacy that asserts that properties of one thing must also be properties of another thing, if both things belong to the same group. For example, a fallacious arguer may claim that "bears are animals, and bears are dangerous; therefore your dog, which is also an animal, must be dangerous."

Hand-waving is a pejorative label for attempting to be seen as effective – in word, reasoning, or deed – while actually doing nothing effective or substantial. It is often applied to debating techniques that involve fallacies, misdirection and the glossing over of details. It is also used academically to indicate unproven claims and skipped steps in proofs, with some specific meanings in particular fields, including literary criticism, speculative fiction, mathematics, logic, science and engineering.

<i>The Demon-Haunted World</i> 1995 book by Carl Sagan

The Demon-Haunted World: Science as a Candle in the Dark is a 1995 book by the astrophysicist Carl Sagan and co-authored by Ann Druyan, in which the authors aim to explain the scientific method to laypeople and to encourage people to learn critical and skeptical thinking. They explain methods to help distinguish between ideas that are considered valid science and those that can be considered pseudoscience. Sagan states that when new ideas are offered for consideration, they should be tested by means of skeptical thinking and should stand up to rigorous questioning.

"God of the gaps" is a theological concept that emerged in the 19th century and revolves around the idea that gaps in scientific understanding are regarded as indications of the existence of God. This perspective has its origins in the observation that some individuals, often with religious inclinations, point to areas where science falls short in explaining natural phenomena as opportunities to insert the presence of a divine creator. The term itself was coined in response to this tendency. This theological view suggests that God fills in the gaps left by scientific knowledge, and that these gaps represent moments of divine intervention or influence.

The existence of God is a subject of debate in theology, philosophy of religion and popular culture. A wide variety of arguments for and against the existence of God or deities can be categorized as logical, empirical, metaphysical, subjective or scientific. In philosophical terms, the question of the existence of God or deities involves the disciplines of epistemology and ontology and the theory of value.

Pseudoskepticism is a philosophical or scientific position that appears to be that of skepticism or scientific skepticism but in reality is a form of dogmatism.

<span class="mw-page-title-main">Marcello Truzzi</span> American sociologist (1935–2003)

Marcello Truzzi was a professor of sociology at New College of Florida and later at Eastern Michigan University, founding co-chairman of the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP), a founder of the Society for Scientific Exploration, and director for the Center for Scientific Anomalies Research.

<span class="mw-page-title-main">Five Ways (Aquinas)</span> Aquinas arguments that there is a real God

The Quinque viæ are five logical arguments for the existence of God summarized by the 13th-century Catholic philosopher and theologian Thomas Aquinas in his book Summa Theologica. They are:

  1. the argument from "first mover";
  2. the argument from universal causation;
  3. the argument from contingency;
  4. the argument from degree;
  5. the argument from final cause or ends.
<span class="mw-page-title-main">Russell's teapot</span> Analogy devised by Bertrand Russell

Russell's teapot is an analogy, formulated by the philosopher Bertrand Russell (1872–1970), to illustrate that the philosophic burden of proof lies upon a person making empirically unfalsifiable claims, as opposed to shifting the burden of disproof to others.

Proving a negative or negative proof may refer to:

The following outline is provided as an overview of and topical guide to atheism:

An ontological argument is a philosophical argument, made from an ontological basis, that is advanced in support of the existence of God. Such arguments tend to refer to the state of being or existing. More specifically, ontological arguments are commonly conceived a priori in regard to the organization of the universe, whereby, if such organizational structure is true, God must exist.

The burden of proof is the obligation on a party in a dispute to provide sufficient warrant for its position.

An argument from authority, also called an appeal to authority, or argumentum ad verecundiam, is a form of argument in which the opinion of an influential figure is used as evidence to support an argument.

<span class="mw-page-title-main">Sagan standard</span> Carl Sagan: "extraordinary claims require extraordinary evidence"

The Sagan standard is the aphorism that "extraordinary claims require extraordinary evidence". It is named for science communicator Carl Sagan, who used the phrase in his 1979 book Broca's Brain and the 1980 television program Cosmos. The standard has been described as fundamental to the scientific method and is regarded as encapsulating the basic principles of scientific skepticism.

References

  1. ↑ "Absence of Evidence Is Not Evidence of Absence". Quote Investigator. 2019-09-17. Retrieved 2021-10-23.
  2. ↑ Sagan, Carl (1997). The Demon-Haunted World: Science as a Candle in the Dark (1st ed.). New York: Ballantine. p. 213. ISBN   0-345-40946-9. OCLC   32855551. Appeal to ignorance—the claim that whatever has not been proved false must be true, and vice versa (e.g., There is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist—and there is intelligent life elsewhere in the Universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we're still central to the Universe.) This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence.
  3. 1 2 Copi, Irving; Cohen, Carl; McMahon, Kenneth (2014). Introduction to Logic (14 ed.). Harlow, UK: Pearson Education Limited. pp. 132–133. ISBN   978-1-292-02482-0.
  4. ↑ Martin, M. (2007). The Cambridge Companion to Atheism. Cambridge Companions to Philosophy. Cambridge University Press. p. 70. ISBN   9780521842709. LCCN   2006005949. [Advocates] of the presumption of atheism... insist that it is precisely the absence of evidence for theism that justifies their claim that God does not exist. The problem with such a position is captured neatly by the aphorism, beloved of forensic scientists, that "absence of evidence is not evidence of absence." The absence of evidence is evidence of absence only in case in which, were the postulated entity to exist, we should expect to have more evidence of its existence than we do.
  5. ↑ Schreuder, Duco A. (2014). Vision and Visual Perception The Conscious Base of Seeing. p. 105.
  6. ↑ Walton, Douglas (1992). "Nonfallacious Arguments from Ignorance". American Philosophical Quarterly. 29 (4): 381–387. ISSN   0003-0481. JSTOR   20014433.
  7. ↑ Altman, Douglas G; Bland, J Martin (1995). "Absence of evidence is not evidence of absence". British Medical Journal. 311 (19 August): 485. doi:10.1136/bmj.311.7003.485. PMC   2550545 . PMID   7647644.
  8. ↑ Roediger, Henry L.; Dudai, Yadin; Fitzpatrick, Susan M., eds. (2007). Science of memory: concepts. Science of memory. London: Oxford Univ. Press. p. 186. ISBN   978-0-19-531044-3. Does the amnestic agent block consolidation, or now reconsolidation, or impair retrieval? Is the memory deficit permanent or is there spontaneous recovery or the possibility of recovering the memory by further treatments or reminders? It is evident that the same logical objection voiced by Weiskrantz (1966)...He warned that experimental amnesia studies are fatally flawed from the outset, since it is not possible to prove the null hypothesis, i.e. the absence of a memory trace.
  9. ↑ Eichenbaum, Howard. "Persistence: Necessary but not Sufficient." Science of memory: Concepts (2007): 193-197.
  10. ↑ Wixted, J. T. "Integrative comments. Forgetting: It's not just the opposite of remembering (2007) Science of memory concepts." 329-335. "However, it would be difficult to establish the complete absence of a trace because it is always possible that an as yet untried retrieval cue would show that some remnant of the trace is still available."
  11. 1 2 Davis, Michael. "Forgetting: Once again, it’s all about representations." Science of memory: Concepts (2007): 317-320.
  12. ↑ Tuzet, Giovanni (2015), Bustamante, Thomas; Dahlman, Christian (eds.), "On the Absence of Evidence", Argument Types and Fallacies in Legal Argumentation, Law and Philosophy Library, Cham: Springer International Publishing, vol. 112, pp. 37–51, doi:10.1007/978-3-319-16148-8_3, ISBN   978-3-319-16148-8 , retrieved 2021-10-21
  13. 1 2 3 Hales, Steven D. (Summer 2005). "Thinking tools: You can prove a negative" (PDF). Think . Cambridge University Press. 4 (10): 109–112. doi:10.1017/S1477175600001287. S2CID   170305277.
  14. ↑ Quine, William Van Orman (1978). The Web of Belief. Random House. p. 8. ISBN   978-0394321790.
  15. ↑ Truzzi, Marcello (August 1987). "Zetetic Ruminations on Skepticism and Anomalies in Science". Zetetic Scholar (12 & 13): 3–4. Retrieved 5 July 2023.
  16. ↑ Damer, T. Edward (2009). Attacking faulty reasoning: a practical guide to fallacy-free arguments. Cengage Learning. p.  17. ISBN   9780495095064.
  17. ↑ "You Can Prove a Negative | Psychology Today". www.psychologytoday.com. Retrieved 2022-11-28.
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