His work advocated a movement beyond reason and metaphysics, arguing that these are incapable of conclusively establishing truth about ultimate problems, including the nature of God or existence.

After emigrating to France in 1921, he befriended and influenced thinkers such as Edmund Husserl, Benjamin Fondane, Rachel Bespaloff,[5] and Georges Bataille.

Shestov's dissertation was rejected by the St. Vladimir's Imperial University of Kiev on account of the revolutionary tendencies it expressed, thus preventing him from becoming a doctor of law.

In 1898 he entered a circle of prominent Russian intellectuals and artists which included Nikolai Berdyaev, Sergei Diaghilev, Dmitri Merezhkovsky and Vasily Rozanov.

During this time he completed his first major philosophical work, Good in the Teaching of Tolstoy and Nietzsche: Philosophy and Preaching; two authors profoundly impacting Shestov's thought.

He developed his thinking in a second book on Fyodor Dostoyevsky and Friedrich Nietzsche, which increased Shestov's reputation as an original and incisive thinker.

In All Things Are Possible (published in 1905) Shestov adopted the aphoristic style of Friedrich Nietzsche to investigate the difference between Russian and European Literature.

Although on the surface it is an exploration of numerous intellectual topics, at its base it is a sardonic work of Existentialist philosophy which both criticizes and satirizes our fundamental attitudes towards life situations.

D. H. Lawrence, who wrote the foreword to S.S. Koteliansky's literary translation of the work,[7] summarized Shestov's philosophy with the words: " 'Everything is possible' - this is his really central cry.

[8] Shestov deals with key issues such as religion, rationalism, and science in this highly approachable work, topics he would also examine in later writings such as In Job's Balances.

He was also close to Eugene and Olga Petit, who helped him and his family relocate to Paris and integrate into the French political and literary circles.

[11] The discovery of Kierkegaard prompted Shestov to realise that his philosophy shared great similarities, such as his rejection of idealism, and his belief that man can gain ultimate knowledge through ungrounded subjective thought rather than objective reason and verifiability.

Despite his weakening condition Shestov continued to write at a quick pace, and finally completed his magnum opus Athens and Jerusalem.

During this final period, he continued his studies, concentrating in particular on Indian philosophy as well as the works of his contemporary and friend Edmund Husserl, who had died recently.

For Shestov, philosophy has employed reason to place humans and God alike in a servile position with respect to "necessities" that are eternally true, unchangeable, and ultimately tyrannical.

[12] Shestov targets this as a repressed flaw in Western philosophy and counters, following Kierkegaard, that God entails the notion that "there is nothing that is impossible"—the absolute need not be limited by reason.

The root of this despair is what he frequently calls 'Necessity', but also 'Reason', 'Idealism' or 'Fate': a certain way of thinking (but at the same time also a very real aspect of the world) that subordinates life to ideas, abstractions, generalisations and thereby kills it, through an ignoring of the uniqueness and livingness of reality.

It is the experience that "everything is possible" (Dostoevsky), that the opposite of Necessity is not chance or accident, but possibility, that there does exist a god-given freedom without boundaries, without walls or borders: Within the “limits of reason” one can create a science, a sublime ethic, and even a religion; but to find G-d one must tear oneself away from the seductions of reason with all its physical and moral constraints, and go to another source of truth.

In Scripture, this source bears the enigmatic name “faith,” which is that dimension of thought where truth abandons itself fearlessly and joyously to the entire disposition of the Creator.

He described the incarnation and resurrection of Jesus as a transfiguring spectacle by which it is demonstrated that the purpose of life is not "mystical" surrender to the "absolute", but ascetical struggle: "Cur Deus homo?

Shestov was highly admired and honored by Nikolai Berdyaev and Sergei Bulgakov in Russia, Jules de Gaultier, Georges Bataille, Lucien Lévy-Bruhl, Paul Celan, Gilles Deleuze, and Albert Camus in France, and D. H. Lawrence, Isaiah Berlin and John Middleton Murry in England.

He did however influence writers such as Albert Camus (who wrote about him in Le Mythe de Sisyphe, The Myth of Sisyphus), Benjamin Fondane (his 'pupil'), the poet Paul Celan, and notably Emil Cioran, who writes about Shestov: Shestov also appears in the work of Gilles Deleuze; he is referred to sporadically in Nietzsche and Philosophy and also appears in Difference and Repetition.

He argues that Shestov's radical views on theology and an interest in extreme human behavior probably coloured Bataille's own thoughts.