Some non-expert meanderings…
Reading Eric Silbin’s The Cello Suites, a book about J.S. Bach, his cello suites, and Pablo Casals, I came across this passage: “When Bach was hired at Cöthen in 1717, the court Capelle consisted of sixteen musicians, the core of whom came from the disbanded Berlin Capelle, courtesy of rising Prussian militarism” (p.63). That was the Capelle that was in Berlin under Frederick I, and disbanded after he died in 1713. Now Frederick I had been married to Sophie Charlotte, who had died in 1705. And Sophie Charlotte is somewhat familiar from the history of modern philosophy, at least because of her connections with Leibniz. Other philosophically engaged figures had connections here too. For example, John Toland travelled there, and described the court in a book, and Leibniz’s correspondent Thomas Burnett, about whom I’ve been writing, had been there too. Thus, for example, Burnett wrote to Catherine Trotter from Berlin on 5 December 1704:
I have no delight in the hearing or seeing any woman, since I came abroad, like the queen, who, never, I believe, spoke, but with satisfaction to the hearer. Her concern for me is so great, that I am ashamed therof. It hath made me many open flatterers, and it may be hidden enemies.
So these philosophical types had been at the court in Berlin. And some of Bach’s musicians in Cöthen had also been at the court in Berlin. So, I wondered, were any of those musicians who moved to Cöthen in 1713 among the musicians who might have been heard by the philosophers in Berlin?
After all, little later in the letter to Trotter quoted above, Burnett tells of how he had contracted a fever one night,
and so could not return to sup at court, nor hear excellent music, that was to be that night, of which her majesty had acquainted me graciously before (p.180).
And Toland wrote of Sophie Charlotte that:
her favorit Diversion is Music, and one must judg as well of it as her Majesty (which is not easily don) to love it with a Passion equal to her’s. She plays to Perfection on the Harpsichord, which she practices every day: she sings finely; and the famous BONONCINI, one of the greatest Masters alive, told me, that her Compositions are most exact (Toland 1705, 33).
Of course, for Burnett or Toland to have heard any of the musicians who became part of Bach’s Capelle, those musicians would have had to have been in Berlin for over a decade. Who were the musicians in question, and how long had they been part of the Berlin Capelle? Christoph Wolff’s Johann Sebastian Bach: the Learned Musician tells us that: “around the beginning of 1713, six distinguished musicians moved from Berlin to the small residential town of the Anhalt-Cöthen principality, some hundred miles away: the capellmeister Augustin Reinhard Stricker and his wife, singer and lutenist Catharina Elisabeth Stricker; oboist Johann Ludwig Rose; violinists Joseph Spieß and Martin Friedrich Marcus, and bassoonist Johan Christoph Torlé. The cellist Carl Bernhardt Lienicke rejoined his former colleagues in 1716 …” (p.194). Though the Strickers left when Bach was appointed as cappelmeister in 1717, Rose, Spieß, Marcus, Torlé, and Lienicke all remained in Cöthen until at least 1722. So the question becomes, was any one of these five heard by the philosophers in Berlin? On music at the Berlin court, see Mary Oleskiewicz, “Music at the Court of Brandenburg-Prussia”, which has an interesting description of the musical environment in the Berlin court. Oleskiewicz also refers to Sachs, Music und Oper, who gives the following dates when the relevant musicians were appointed to the Capelle in Berlin: Rose, 1708; Spieß, 1710; Marcus (“Marx (Marcks)”) 1708; Torley, 1706; and Lienicke (“Linigke, Christian Bernhard, Violoncellist”), 1706. What that means is that none of these musicians of Bach’s could have been heard as part of the Berlin Capelle by Burnett, who was last in Berlin in 1704. But Toland was back in Berlin as late as 1708. And Leibniz was in Berlin after that: he was in Berlin from December 1706 to May 1707, January to March 1709, and on a last visit in Feb – May 1711 (Antognazza, Leibniz, 463–8).
None of this guarantees that any of the musicians who later worked with Bach were actually heard by Toland or Leibniz. But they might have been. And there is an interesting connection here between aspects of the seventeenth-century world that are usually thought of quite separately.
 The Works of Mrs Catherine Cockburn (London, 1751), 2.179). The “George Burnett” of Trotter’s works is the man better known as Thomas Burnett of Kemnay. This becomes clear if you read the Trotter-Burnett correspondence together with the Leibniz-Burnett correspondence. I note that Burnett (1901) is well aware of a Burnett-Trotter correspondence, as is the editor of Locke’s correspondence (Correspondence 6.60).
 Not that it was all high culture all the time in Berlin: Toland also described “a stately Amphitheatre for the fighting and baiting of Bears, Lions, Bulls, Urochsen which are the Uri of the Ancients, and of other wild and fierce Beasts, of which a good Number is always kept underneath in their Dens” (Toland 1705, 19).
 In Music at German Courts, 1715–1760: Changing Artistic Priorities, ed. Samantha Owens, Barbara M. Reul, and Janice B. Stockigt (Woodbridge, Suffolk, U.K.: Boydell and Brewer, 2011), 79–130.
 There are certainly papers on Leibniz and Bach, but my (admittedly far from perfectly well informed) impression is that they tend to involve thinking about Bach in the light of some aspect of Leibniz’s philosophy, rather than the sort of connection I’ve been wondering about here.