PARIS — European history has shown, time and again, that anti-Semitism is an indicator that the social state has become unstable. It's therefore not shocking that it's developing today in France, linked in particular to fringes of the anti-establishment yellow vest movement. The paths laid between a society in crisis and anti-Semitism have been laid in the collective subconscious. Jews are often perceived as belonging to the elite, notably the intellectual and financial elite; and thus when a movement attacks the elite, it quickly moves to attacking Jews.

An additional noteworthy factor: There are very real extremist infiltrations into the Yellow Vests ("Gilets Jaunes') movement. And these extremists, despite their ideological differences, have two points in common that have come up throughout history: the rejection of "the system"— whatever that's supposed to mean — and that of the Jews. Hence improbable alliances between socialists and nationalists of which Nazism was the worst example.

Our societies have been facing growing instability for decades. There is an unprecedented level of interaction between people, cultures and businesses that creates a constant acceleration of change, of which globalization is but one aspect. The Yellow Vests movement is an expression of the anxiety created by this increasingly complex reality.

We are living in a dangerous time.

In response to this, certain people are looking for that which is simple — or, simplistic — and stable. This is an open door for nationalist or religious authoritarianism in which the demagogue reassures individuals with supposedly collective certainties. Until now, this call for strong power and at the exclusion of "others' has only appeared under immediate crises, like that of 1929. But when instability pulls at the nerves of a society in the long term, the ability to develop one's own benchmarks is the only alternative.

In the 20th century, this drove ordinary societies to genocide in a process and chain of events fed by extremism — in particular, extremism that's centered on identity and that winds up in search of scapegoats. This kind of chain of events can lead to a toppling of institutions, which does not necessarily mean a change of regime. This can occur with the gradual tightening of laws, public discourse from the leadership or the opposition around themes focusing on security over liberty, identity over politics or social concerns. Right now, we are in a volatile climate, where each action, each actor, each institution can be the difference between fostering or threatening civil peace.

Paris protests on Jan. 26 — Photo: Bruno Thevenin/SOPA Images/ZUMA

There is no use in preserving the memory of tragic experience if we forget that an authoritarian regime can be established anew in France. Fortunately, history also shows us that the process can be resisted, provided we resist it. But I'm very worried, even if the French people still seem rather level-headed.

We are living in a dangerous time, but it can also be a chance to allow us to progress on questions of equality and to improve our democracy — a bit like after the May 1968 movement that sparked many important questions about our relationship to consumption, the direction of progress, the relationship between men and women.

It can be resisted, provided we resist it.

We must quickly and strongly react to social unrest, notably on the questions of the distribution of wealth and the evolution of forms of democratic consultation and decision-making. Political power is just one actor of change and we should probably try to make our peace with its imperfect results, divided between quick decisions and processes that necessarily take more time. And of course, if we aim to involve citizens at all stages, we will need to wisely use new technologies.

One part of the immediate future will involve the relationship between reason and passion. The platform for dialogue exists, as social justice, equality, and dignity are values we share. But democratic dialogue cannot function without a basic level of reason. Democracy can die when that is replaced by an eruption of violence, no matter the origin, based on fear and hatred.