The work exhibits Lutosławski's technique of "limited aleatoricism", where the individual instrumental parts are notated exactly, but their precise co-ordination is organised using controlled elements of chance.

The Soviet Union under Joseph Stalin had seized control of the country in the aftermath of World War II, and the iron-fisted cultural dictation of the Communist government severely limited both the output of Polish composers and their exposure to musical developments in the outside world between the 1949 and 1954.

Many pieces, including Lutosławski's first symphony, were condemned as formalist (focused on esoteric considerations of form rather than on speaking directly to the proletariat) and banned from public performance.

The years between the end of World War II and its completion had been a continuous effort to cement his personal style.

[6] Lutosławski had completed his first symphony in 1947—a work that some have called neoclassicist in its extensive use of canon and adherence to the 4-movement standard and sonata form in the first movement.

In the process of composing Five Songs on texts of Kazimiera Iłłakowicz (1956–1958), Muzyka żałobna (1958), Three Postludes (1959–1964), and Jeux vénitiens (1960–1), he developed the harmonic and rhythmic elements that define the Symphony No.

[8] These hallmarks of Lutosławski's new style include harmonic aggregate chords using all twelve tones, macrorhythmic accelerando, texture as a formal element, and a preference for grouping instruments with similar colors.

[9] When Lutosławski heard John Cage's piano concerto, he began exploring limited aleatoricism, and this became a feature of his style, although he intentionally never extended his employment of chance techniques beyond rhythm.

[14] Unfortunately, the entire symphony was not completed in time for the concert in Hamburg, so only the second movement, Direct, was performed by the Norddeutscher Rundfunk with Pierre Boulez conducting, on October 18, 1966.

[17] The orchestra, as specified in the score: Instrumentation plays an important role in the first movement of the work, where six episodes are performed by different ensembles.

Instrumentation in "Hésitant" (all locations given by conductor's marked downbeats on the score): The second symphony is the first large-scale work for orchestra to use Lutosławski's new conception of two-movement form.

Lutosławski connects this feeling of proportion, especially in the presence of only one emotionally and semantically complex movement, to the symphonies of eighteenth-century Vienna and Haydn in particular.

A simple example of a melodic trait of closed form is the use and fragmentation of motives; a harmonic example is the use of progressions to lure the listener to expect something, such as a climax or an ending.

[27] This process pushes to the climax of the movement and the symphony as a whole, which occurs When the simple rhythm, which has been achieved gradually over a considerable period, is transformed suddenly into an extremely complex rhythmical structure when the whole orchestra begins to play ad libitum.

[28] Harmonically, the climax of this piece is marked by a twelve-tone chord based on 5ths and 6ths that falls away and almost immediately makes another effort.

Lutosławski lists several criteria for a symphony: it must be a large-scale piece – "A ten-minute piece of music shall not be referred to as a symphony"; it must be a closed form, thus excluding much music based on Cage's aesthetic; it must be written for the symphonic orchestra; and most importantly, "it must be properly shaped into a process with a perceptible akcja (i.e., action).

Most theories return to an analytical approach to musical characters developed by Lutosławski's mentor, Witold Maliszewski.

[33] Akcja then, in Reyland's view, consists of the interaction, evolution, and transformation of key ideas throughout a musical work.

[37] A full analysis of this symphony in terms of akcja would trace the development of this and other key ideas (perhaps the first movement's refrain) throughout the work.

In an interview about the symphony with Tadeusz Kaczyński in 1967, he stated that "music is not meant to express anything in an unambiguous manner" and therefore a concrete meaning of the piece "would not have much sense.

"[38] Michael Klein proposes that the perception of long-range formal trajectories in Lutosławski's music of the 1960s and 1970s may be enhanced by the analysis of transformations on register, or texture-space.

Although each of the parts is relatively simple in terms of rhythm and melody, the composite pitch and rhythmic structures in these ad libitum sections can become complex.

The composite constructed of each part's structural tones, in pitch space, is understood as the harmonic complex underpinning the section.

As Lutosławski's musical career progressed, he began to cement his ideas and beliefs concerning the symphony orchestra, forms, and many other aspects of composition.

Lutosławski also commented on modified symphony instruments and extended technique, saying that altering the use of these "great works of art" is "unnatural" and "jarring".

[8] These ideas led Lutosławski to look ahead to a time when the orchestra would be replaced by an ensemble that could produce what he already heard in his head.