Can someone explain to me with an example what a predictive conditional is?

Does this type of conditional have necessary and sufficient conditions?

  • See comments and link to the post : Truth value of predictive conditional – Mauro ALLEGRANZA Sep 15 '18 at 11:38
  • I made an edit which you may roll back or continue editing. You can see the versions by clicking on the "edited" link above. The links Mauro ALLEGRANZ referenced in the other question are worth checking. Welcome to this SE! – Frank Hubeny Sep 15 '18 at 12:58

The link Mauro ALLEGRANZA referenced in the similar question contains some examples of a predictive conditional:

A predictive conditional sentence concerns a situation dependent on a hypothetical (but entirely possible) future event. The consequence is normally also a statement about the future, although it may also be a consequent statement about present or past time (or a question or order).

If I become President, I'll lower taxes.

If it rains this afternoon, everybody will stay home.

If it rains this afternoon, then yesterday's weather forecast was wrong.

If it rains this afternoon, your garden party is doomed.

What will you do if he invites you?

If you see them, shoot!

These examples should answer the first question.

The second question is whether these statements have necessary and sufficient conditions. These concepts are relevant for material conditionals. If one can symbolize the English predictive conditional as a material implication, A → B, then one can use that to find the necessary and sufficient conditions. As defined in forallx: Calgary Remix (page 33):

A sentence can be symbolized as A → B if it can be paraphrased in English as ‘If A, then B’ or ‘A only if B’.


P. D. Magnus, Tim Button with additions by J. Robert Loftis remixed and revised by Aaron Thomas-Bolduc, Richard Zach, forallx Calgary Remix: An Introduction to Formal Logic, Winter 2018. http://forallx.openlogicproject.org/ Wikipedia, "Fitch notation" https://en.wikipedia.org/wiki/Fitch_notation

Wikipedia, "Conditional sentence" https://en.wikipedia.org/wiki/Conditional_sentence#Implicative_and_predictive

Wikipedia, "Material conditional" https://en.wikipedia.org/wiki/Material_conditional

Wikipedia, "Necessity and sufficiency" https://en.wikipedia.org/wiki/Necessity_and_sufficiency

  • RE: "If I become president, then I'll lower taxes." This does not seem like a conditional statement to me. It is a promise that may or may not be kept. Or a prediction that may or may not come true. It cannot be used to draw any conclusions about future events. How then is it "predictive?" It seems to defy any logical analysis. Why are such statements worthy of serious consideration in philosophy or mathematics? – Dan Christensen Sep 16 '18 at 4:39
  • @DanChristensen I agree with you. It may also be a lie. I see the idea of "predictive conditional" as a way to describe English sentences. If one can convert it into a material conditional, then one can do the logical analysis on it. Even if one paraphrases the English conditional sentence so it looks like a material conditional that doesn't mean the paraphrase was accurate. The English sentence may contain critical ambiguities that the paraphrasing carelessly throws away to convert the English conditional into a material conditional.. – Frank Hubeny Sep 16 '18 at 10:59
  • For what it is worth, a material-conditional version might be: "If I am president, then taxes are lower" (using the present tense for antecedent and consequent). – Dan Christensen Sep 16 '18 at 12:56
  • If it helps, this list mixes modalities, so whether these are examples depends upon whether you are considering modal logics of different varieties. If so, prediction is necessarily in the alethic mode: it is a statement about consequences. Promises are in the optative mode: they are about intentions. Orders are in the deontic mode, they extend one obligation (to respect the speaker) to another one (to take a given action). Each mode has its own dual necessary and sufficient conditions: facts are necessary, or duties are necessary, or what one is unwilling to live without is necessary. – user9166 Aug 11 '19 at 20:49
  • @jobermark It is good to point that out. Thanks. – Frank Hubeny Aug 11 '19 at 23:40

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