The philosophy of music by Alexei Losev will be examined through one of the most mysterious fragments of his work "Music as an Object of Logic". In the book "Music as an Object of Logic", Alexei Losev attempted to describe music as a special type of being that cannot be reduced to familiar logical schemes. One of the most enigmatic fragments of this work became the discussion of "meonal numbers". Seminar participants will explore this complex episode and try to find modern meaningful analogues. Vladimir Troitsky's report will be built at the intersection of philosophy, mathematics, and music. Listeners will learn which concepts from modern mathematics, including algebraic geometry, can help interpret Losev's constructions. The theoretical part will be supplemented with musical examples from the works of composers of the 19th and 20th centuries. They will help trace how discussions about form, number, and musical object relate to real sound. Admission is free; tickets can be booked online in advance or obtained at the box office of the Losev House before the event starts. Additionally, visitors will be able to view the museum's temporary exhibitions for free.