The origin of sets? - MathOverflow most recent 30 from http://mathoverflow.net 2013-06-20T08:53:10Z http://mathoverflow.net/feeds/question/117051 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/117051/the-origin-of-sets The origin of sets? François G. Dorais 2012-12-22T21:32:43Z 2013-01-03T03:42:02Z <p>The history of <em>set theory</em> from Cantor to modern times is well documented. However, the origin of the <em>idea of sets</em> is not so clear. A few years ago, I taught a set theory course and I did some digging to find the earliest definition of sets. My notes are a little scattered but it appears that the one of the earliest definition that I found was due to Bolzano in <em>Paradoxien des Unendlichen</em>:</p> <blockquote> <p>There are wholes which, although they contain the same parts $A$, $B$, $C$, $D$,..., nevertheless present themselves as different when seen from our point of view or conception (this kind of difference we call 'essential'), e.g. a complete and a broken glass viewed as a drinking vessel. [...] A whole whose basic conception renders the arrangement of its parts a matter of indifference (and whose rearrangement therefore changes nothing essential from our point of view, if only that changes), I call a set.</p> </blockquote> <p>(The original German text is <a href="http://books.google.com/books?id=1YU3AAAAMAAJ&amp;pg=PA4#v=onepage&amp;q&amp;f=false" rel="nofollow">here</a>, &sect;4; I don't remember where I got the translation.)</p> <p>According to my notes, Bolzano wrote this in 1847. Since Boole's <em>An Investigation of the Laws of Thought</em> was published a just few years later in 1854, it seems that the idea of sets was already well known at that time.</p> <blockquote> <p><em>What was the earliest definition of 'set' in the mathematical literature</em>?</p> </blockquote> <p>Historical queries of this type are hopelessly vague, so let me give some more specific criteria for what I am looking for. The object doesn't have to be called "set" but it must be an independent container object where the arrangement of the parts doesn't matter.</p> <ul> <li>It should also be fairly general in what the set can contain. A general set of points in the plane is probably not enough in terms of generality but if the same concept is also used for collections of lines then we're talking.</li> <li>It shouldn't have implicit or explicit structure. Line segments, intervals, planes and such are too structured even if the arrangement of the parts technically doesn't matter.</li> <li>It should be an independent object intended to be used and manipulated for its own sake. For example, the first time a collection of points in general position was considered in the literature doesn't make the cut since there was no intent to manipulate the collection for its own sake.</li> <li>It should be a definition. Formal definitions as we see them today are a relatively new phenomenon but it should be fairly clear that this is the intent, such as when Bolzano says "I call a set" at the end of the quote above.</li> <li>It should be mathematical concept. The strict divisions we have today are very recent but it should be clear that the sets in question are intended for mathematical purposes. <em>Paradoxien des Unendlichen</em> is perhaps more of a philosophical treatise than a mathematical one, but it is clear that Bolzano is considering sets in a mathematical way.</li> </ul> <p>That said, any input that doesn't quite meet all of these criteria is welcome since the ultimate goal is to understand how the modern idea of set came to be.</p> http://mathoverflow.net/questions/117051/the-origin-of-sets/117052#117052 Answer by Kevin O'Bryant for The origin of sets? Kevin O'Bryant 2012-12-22T22:46:31Z 2012-12-27T04:18:46Z <p>"<a href="http://books.google.com/books?id=S4ENlDtLppAC&amp;pg=PA325&amp;dq=%2522set+of+numbers%2522&amp;hl=en&amp;sa=X&amp;ei=WjfWUO6OKoaI0QGA0oHgCA&amp;ved=0CGAQ6AEwBg#v=onepage&amp;q=%2522set%2520of%2520numbers%2522&amp;f=false" rel="nofollow">A new and compendious system of practical arithmetick</a>", by William Pardon in 1738, contains the passage:</p> <blockquote> <p>Here if the first <em>Series</em> or Set of <em>Numbers</em> increases by 1, and the second decreases by 1; the third increases by 2, ...</p> </blockquote> <p>The emphasis is in the original, so that it is not <em>set</em> that is being described. So in 1738, it's meaning was already taken for granted.</p> http://mathoverflow.net/questions/117051/the-origin-of-sets/117053#117053 Answer by Tom Leinster for The origin of sets? Tom Leinster 2012-12-22T22:51:03Z 2012-12-22T22:51:03Z <p>This isn't meant entirely seriously as an answer to your question, but: on page 344 of <em>Practical Foundations of Mathematics</em>, Paul Taylor writes:</p> <blockquote> <p>Adam of Balsham (1132) observed that the difference between finite and infinite sets is that the latter admit proper self-inclusions, such as $n \mapsto 2n$.</p> </blockquote> <p>Obviously this is staggeringly early and it would be astonishing if this dude Adam had anything like our present-day conception of set. Paul doesn't appear to give a reference, but perhaps he (Paul, not Adam) will see this and tell us more.</p> http://mathoverflow.net/questions/117051/the-origin-of-sets/117063#117063 Answer by Francois Ziegler for The origin of sets? Francois Ziegler 2012-12-23T02:26:24Z 2012-12-27T13:42:34Z <p>Euler in <em><a href="http://archive.org/stream/lettresdeleuleru01eule#page/410/" rel="nofollow">Lettres à une princesse d'Allemagne sur divers sujets de physique et de philosophie</a></em>, 17-24 feb 1761, writes about objects he calls <strong>spaces</strong> (my emphasis):</p> <blockquote> <p>As a general notion encompasses an infinity of individual objects, one regards it as a <strong>space</strong> within which all these individuals are enclosed: thus, for the notion of <em>man</em>, one makes a <strong>space</strong> (fig. 39) in which one conceives that all men are comprised. For the notion of <em>mortal</em>, one also makes a <strong>space</strong> (fig. 40), where one conceives that everything mortal is comprised. Then, when I say that <em>all men are mortal</em>, that comes down to the former figure being contained in the latter.</p> <p>(...)</p> <p>These round figures or rather these <strong>spaces</strong> (for it doesn't matter what shape we give them) are very well-suited to facilitating our reflections (...)</p> </blockquote> <p>etc., and illustrates this with what we would call ensemblist <a href="http://archive.org/stream/lettresdeleuleru01eule#page/n532/mode/1up" rel="nofollow">diagrams (fig. 39 to 89)</a>, famously reproduced on <a href="http://en.wikipedia.org/wiki/File%3AEuler-10_Swiss_Franc_banknote_%28front%29.jpg" rel="nofollow">Swiss banknotes</a>. The applications he gives here are to everyday logic, so perhaps less mathematical than intended by the question. (I don't know if he ever wrote again on the subject.)</p> http://mathoverflow.net/questions/117051/the-origin-of-sets/117076#117076 Answer by Stxmqs for The origin of sets? Stxmqs 2012-12-23T09:23:33Z 2012-12-24T07:14:19Z <p>From the Wikipedia article on Euler diagrams:</p> <p>"The first use of "Eulerian circles" is commonly attributed to Swiss mathematician Leonhard Euler (1707–1783)."</p> <p>"Venn diagrams are a more restrictive form of Euler diagrams. A Venn diagram must contain all 2n logically possible zones of overlap between its n curves, representing all combinations of inclusion/exclusion of its constituent sets, but in an Euler diagram some zones might be missing if they are empty sets."</p> <p><img src="http://en.wikipedia.org/wiki/File%3aEuler-venn-example.png" alt="Eulerian circles"></p> http://mathoverflow.net/questions/117051/the-origin-of-sets/117926#117926 Answer by milo gardner for The origin of sets? milo gardner 2013-01-03T03:42:02Z 2013-01-03T03:42:02Z <p>high school math used sets to define the domain of the numbers in play ... in advance ... college sets added Venn diagrams ... but not much more ...</p>