Which came first, the ##\exists## or the ##\forall##?

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Discussion Overview

The discussion revolves around the historical origins and notational development of the mathematical quantifiers "for all" (##\forall##) and "there exists" (##\exists##). Participants explore various hypotheses regarding how these symbols were created and their evolution in mathematical logic.

Discussion Character

  • Exploratory
  • Historical

Main Points Raised

  • One participant humorously speculates on the possible scenarios in which the symbols for "for all" and "there exists" were derived from flipping letters.
  • Another participant cites historical context from Wikipedia, mentioning the influence of logicians like Peirce, Johnson, and Peano on the notation for quantification.
  • A later reply notes that both symbols can be rotated through 180 degrees, suggesting a practical aspect of symbol creation in historical typesetting.

Areas of Agreement / Disagreement

Participants do not reach a consensus on which quantifier came first, and the discussion remains open-ended with multiple speculative viewpoints presented.

Contextual Notes

There are references to historical figures and their contributions to the notation, but the discussion does not resolve the specific timeline or definitive origins of the symbols.

1MileCrash
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I've always imagined that some mathematician or logician was looking for a cool way to write these quantifiers, and one of the following scenarios happened:

1.)

"Hey, I know, for "For All," I'll just take the letter "A" and flip it vertically, giving me this lovely ##\forall##. Then I'll just do the same thing with the letter "E" for "There Exists."

But wait, the letter "E" is vertically symmetric, it'll look the same!" *flips it horizontally instead.


2.)

"Hey, I know, for "There Exists," I'll just take the letter "E" and flip it horizontally, giving me this lovely ##\exists##. Then I'll just do the same thing with the letter "A" for "For All."

But wait, the letter "A" is horizontally symmetric, it'll look the same!" *flips it vertically instead.



So the question is, what came first, the ##\forall## or the ##\exists##?
 
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From wiki:

Peirce's approach to quantification also influenced William Ernest Johnson and Giuseppe Peano, who invented yet another notation, namely (x) for the universal quantification of x and (in 1897) ∃x for the existential quantification of x. Hence for decades, the canonical notation in philosophy and mathematical logic was (x)P to express "all individuals in the domain of discourse have the property P," and "(∃x)P" for "there exists at least one individual in the domain of discourse having the property P." Peano, who was much better known than Peirce, in effect diffused the latter's thinking throughout Europe. Peano's notation was adopted by the Principia Mathematica of Whitehead and Russell, Quine, and Alonzo Church. In 1935, Gentzen introduced the ∀ symbol, by analogy with Peano's ∃ symbol. ∀ did not become canonical until the 1960s.

http://en.wikipedia.org/wiki/Quantification
 
Another mystery dispelled by wikipedia.
 
1MileCrash said:
But wait, the letter "E" is vertically symmetric, it'll look the same!" *flips it horizontally instead.

But wait, the letter "A" is horizontally symmetric, it'll look the same!" *flips it vertically instead.
True but probably irrelevant. Both symbols are rotated through 180 degrees.

Before computer typesetting, using metal type "upside down" was an easy way to get new symbols.
 

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