Philosophic burden of proof
The philosophical burden of proof or onus (probandi) is the obligation on a party in an epistemic dispute to provide sufficient warrant for their position.
Holder of the burden
When debating any issue, there is an implicit burden of proof on the person asserting a claim. An argument from ignorance occurs when either a proposition is assumed to be true because it has not yet been proven false or a proposition is assumed to be false because it has not yet been proven true. This has the effect of shifting the burden of proof to the person criticizing the assertion, but is not valid reasoning.
While certain kinds of arguments, such as logical syllogisms, require mathematical or strictly logical proofs, the standard for evidence to meet the burden of proof is usually determined by context and community standards.
In public discourse
Burden of proof is also an important concept in the public arena of ideas. Once participants in discourse establish common assumptions, the mechanism of burden of proof helps to ensure that all parties contribute productively, using relevant arguments.
Proving a negative
When the assertion to prove is a negative claim, the burden takes the form of a negative proof, proof of impossibility, or mere evidence of absence. If this negative assertion is in response to a claim made by another party in a debate, asserting the falsehood of the positive claim shifts the burden of proof from the party making the first claim to the one asserting its falsehood, as the position "I do not believe that X is true" is different to the explicit denial "I believe that X is false".
Matt Dillahunty gives the example of a large jar full of gumballs to illustrate the burden of proof. It is a fact of reality that the number of gumballs in the jar is either even or odd, but the beliefs a person could hold are more complicated. We can choose to consider two claims about the situation, given as
- The number of gumballs is even.
- The number of gumballs is odd.
These two claims can be considered independently. For each claim, because of the law of excluded middle, we are forced to either believe or not believe. Before we have any information about the number of gumballs, we have no means of distinguishing either of the two claims. All of the information we have applies to claim 1 in exactly the same way it applies to claim 2. Due to the law of noncontradiction we cannot accept both of the two mutually exclusive claims, so we must reject (or not believe) both. This is the default position, which represents the null hypothesis. The justification for this position is only ever the lack of evidence supporting a claim. Instead, the burden of proof, or the responsibility to provide evidence and reasoning, lies with those seeking to persuade someone holding the default position.
- Legal burden of proof
- Scientific consensus
- Scientific method
- Statistical hypothesis testing
- Russell's teapot
- "Argumentum ad Ignorantiam". Philosophy 103: Introduction to Logic. Lander University. 2004. Archived from the original on 30 April 2009. Retrieved 2009-04-29.
- Dowden, Bradley. "Appeal to Ignorance". Internet Encyclopedia of Philosophy.
- Michalos, Alex (1969). Principles of Logic. Englewood Cliffs: Prentice-Hall. p. 370. "usually one who makes an assertion must assume the responsibility of defending it. If this responsibility or burden of proof is shifted to a critic, the fallacy of appealing to ignorance is committed."
- Leite, Adam (2005). "A Localist Solution to the Regress of Justification". Australasian Journal of Philosophy 83 (3): 395–421 [p. 418]. doi:10.1080/00048400500191974. "[t]he point of articulating reasons in defense of one’s belief is to establish that one is justified in believing as one does."
- Leite, Adam (2005). "A Localist Solution to the Regress of Justification". Australasian Journal of Philosophy 83 (3): 395–421 [p. 403]. doi:10.1080/00048400500191974. "justificatory conversation...[is]...characterized by a person’s sincere attempt to vindicate his or her entitlement to a belief by providing adequate reasons in its defense and responding to objections."
- Goldman, Alvin (1994). "Argumentation and Social Epistemology". Journal of Philosophy 91 (1): 27–49. JSTOR 2940949.
- Eemeren, Frans van; Grootendorst, Rob (2004). A Systematic Theory of Argumentation. Cambridge: Cambridge University Press. p. 60. ISBN 0521830753. "[t]here is no point in venturing to resolve a difference of opinion through an argumentative exchange of views if there is no mutual commitment to a common starting point."
- Brandom, Robert (1994). Making it Explicit. Cambridge: Harvard University Press. p. 222. ISBN 067454319X. "[t]here are sentence types that would require a great deal of work for one to get into a position to challenge, such as 'Red is a color,' 'There have been black dogs,' 'Lighting frequently precedes thunder,' and similar commonplaces. These are treated as 'free moves' by members of our speech community—they are available to just about anyone any time to use as premises, to assert unchallenged."
- Adler, Jonathan (2002). Belief’s Own Ethics. Cambridge: MIT Press. pp. 164–167. ISBN 0262011921.
- T. Edward Dame (2009). Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments. Cengage Learning. p. 17. ISBN 0495095060, 9780495095064 Check
- "The Atheist Experience". Episode 808. 7 April 2013. channelAustin 16. http://www.youtube.com/watch?v=Ek4M1trIYr8.
- Matt Dillahunty (2013). Does God Exist? (Debate). Texas State University.