Cer­tain­ly three of the most rad­i­cal thinkers of the last 150 years, Niet­zsche, Hei­deg­ger, and Sartre were also three of the most con­tro­ver­sial, and at times polit­i­cal­ly tox­ic, for their per­ceived links to total­i­tar­i­an regimes. In Nietzsche’s case, the con­nec­tion to Nazism was whol­ly spu­ri­ous, con­coct­ed after his death by his anti-Semit­ic sis­ter. Nev­er­the­less, Nietzsche’s phi­los­o­phy is far from sym­pa­thet­ic to equal­i­ty, his pol­i­tics, such as they are, high­ly unde­mo­c­ra­t­ic. The case of Hei­deg­ger is much more disturbing—a mem­ber of the Nazi par­ty, the author of Being and Time noto­ri­ous­ly held fas­cist views, made all the more clear by the recent pub­li­ca­tion of his infa­mous “black note­books.” And Sartre, author of Being and Noth­ing­ness, has long been accused of sup­port­ing Stalinism—a charge that may be over­sim­pli­fied, but is not with­out some mer­it.

Despite these trou­bling asso­ci­a­tions, all three philoso­phers are often held up as representatives—along with Søren Kierkegaard and Albert Camus—of Exis­ten­tial­ism, broad­ly a phi­los­o­phy of free­dom against oppres­sive reli­gious and polit­i­cal sys­tems that seek to define and order human life accord­ing to pre­de­ter­mined val­ues. Whether all three thinkers deserve the label (Hei­deg­ger, like Camus, flat­ly reject­ed it) is a mat­ter of some dis­pute, and yet, the BBC doc­u­men­tary series Human, All Too Human, named for Nietzsche’s 1878 col­lec­tion of apho­risms, loose­ly uses the term to tie them togeth­er, acknowl­edg­ing that it had yet to be coined in Nietzsche’s time.

The first episode, at the top, intro­duces the great 19th cen­tu­ry Ger­man athe­ist by way of inter­views with Niet­zsche schol­ars and biog­ra­phers. Episode two cov­ers Hei­deg­ger, with frank dis­cus­sions of his Nazi par­ty affil­i­a­tion and its impli­ca­tions for his thought.

The third episode focus­es on Sartre, the only thinker of the three to call him­self an exis­ten­tial­ist. Both Sartre and his part­ner Simone de Beau­voir wrote on the sub­ject, defend­ing the philo­soph­i­cal out­look in essays and inter­views.

In one of Sartre’s most famous defens­es, “Exis­ten­tial­ism and Human Emo­tion,” he emphat­i­cal­ly defines his philo­soph­i­cal stance as anti-essen­tial­ist and atheistic—unlike the Chris­t­ian Kierkegaard before him.

Athe­is­tic exis­ten­tial­ism, which I rep­re­sent, is more coher­ent. It states that if God does not exist, there is at least one being in whom exis­tence pre­cedes essence, a being who exists before he can be defined by any con­cept, and that this being is man, or, as Hei­deg­ger says, human real­i­ty. What is meant here by say­ing that exis­tence pre­cedes essence? It means that, first of all, man exists, turns up, appears on the scene, and, only after­wards, defines him­self. If man, as the exis­ten­tial­ist con­ceives him, is inde­fin­able, it is because at first he is noth­ing. […] Thus, there is no human nature, since there is no God to con­ceive it. Not only is man what he con­ceives him­self to be, but he is also only what he wills him­self to be after this thrust toward exis­tence.

Exis­ten­tial­ism has become a wide net, used to cap­ture sim­i­lar­i­ties in the work of oth­er­wise wide­ly diver­gent thinkers. How­ev­er, the use of the term his­tor­i­cal­ly belongs to the 1940s and 50s, to a move­ment as much lit­er­ary as philo­soph­i­cal, and Sartre was its great­est cham­pi­on and, some would say, the only true Exis­ten­tial­ist philoso­pher. Nev­er­the­less, the label cap­tures some­thing of the dar­ing and the dan­ger of rad­i­cal phi­los­o­phy that rede­fines, or out­right rejects, tra­di­tion­al norms. For all their flaws and con­tra­dic­tions, all three of the thinkers pro­filed above made sig­nif­i­cant con­tri­bu­tions to our under­stand­ing of what it means to be human—and to be an individual—in an increas­ing­ly mech­a­nized, homog­e­nized, and dehu­man­iz­ing civ­i­liza­tion.

Relat­ed Con­tent:

Wal­ter Kaufmann’s Clas­sic Lec­tures on Niet­zsche, Kierkegaard and Sartre (1960)

Mar­tin Hei­deg­ger Talks About Lan­guage, Being, Marx & Reli­gion in Vin­tage 1960s Inter­views

Philosophy’s Pow­er Cou­ple, Jean-Paul Sartre and Simone de Beau­voir, Fea­tured in 1967 TV Inter­view

100 Free Phi­los­o­phy Cours­es Online

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness