During a private audience with the Lubavitcher Rebbe, Rabbi Menachem Mendel Schneerson, of righteous memory, a bureau chief for a national Jewish newspaper extolled his periodical: “Our publication is independent and completely objective.”

The Rebbe responded pointedly: “Independent, perhaps — but objective? There is no such thing. It is humanly impossible to be completely objective.

“Every person has a bias of some kind.”

I understand the Rebbe’s words to mean that while one can live without an agenda, one cannot live without bias.

Through a mix of nature, nurture and free will, we each possess a certain lens that frames, forms, clouds and distorts the way we see ourselves, others and the world around us. It is simply not possible to erase all traces of our personality, past experiences and deeply-held beliefs from our observations, expressions, or actions — no matter how hard we may try.

This frame that we adopt, whether consciously or unconsciously, deeply impacts the way we perceive reality.

This matrix of understanding becomes our operating system, so to speak — the default mechanism through which we construe and contextualise, react and reinforce, interpret and identify every event and interaction we experience.

Based on this fact of subjectivity, the following questions arise: what are our biases? What are the default frames through which we see the world? How can they be adjusted to better serve ourselves and others?

If our biases inevitably colour the way we interpret and experience the world, it follows that a primary focus of life should be to assess and reset our biases.

In the penetrating words of the Rebbe to an individual who was wont to complain about his life circumstances: “In our world, everything is a mixture of good and bad. Human beings must choose which aspects they will emphasise, contemplate, and pursue…

“How instructive is that which our sages tell us, that Adam was an ingrate. Even before he was banished from the Garden of Eden (while living in a literal paradise), he complained about his circumstances.

“On the other hand, there were Jewish men and women who thanked and blessed the Creator and recited the morning blessings while living through the most horrifying times in the German concentration camps. Ultimately, everyone’s circumstances will be somewhere between these two extremes.

“My point in saying this is not to admonish you; it is simply to underscore the reality: that the type of lives that we live, whether full of satisfaction and meaning or the opposite, depends, in large measure, on our willpower, which dictates whether we will focus on the positive or on the negative.”

Our perspectives are so powerful, they can lead us to find fault with Paradise or to express gratitude even while in a state of extreme suffering.

In a rare personal disclosure to one of his Chasidim and a trusted confidante, Rabbi Berel Junik, the Rebbe once alluded to his focus on seeing things positively as stemming from his harrowing past, saying, “I worked on myself to always look at things in a positive light; otherwise I could not have survived.”

This deceptively simple statement encapsulates the basic premise of my new book; namely, that living a life of positivity derives from perspective, not personality.

It is not the events of our lives that shape us, but the meanings we assign to those events.

In other words: if you change the way you look at things, the things you look at change.

Ultimately, the greatest testing grounds for any theory is the Laboratory of Life.

And that is what makes this book on positivity different from many. For if, as the saying goes, history is philosophy teaching through examples, the book teaches the philosophy of positivity by way of a living example, demonstrating how the Rebbe interacted with real people reacting in real time to real-life situations.

It is important to note that the redemptive perspectives presented are not those of a man who lived a life of peace and privilege. They are the insights of a man who lived through waves of pogroms, the killing fields of World War I, a typhus epidemic, a refugee crisis, the persecution and forced exile of his father, whom he never saw again, the Bolshevik Revolution, the rise of Communism, World War II, the brutal murder of his brother, grandmother, and numerous other relatives at the hands of the Nazis, and a life of childlessness.

They are the teachings of a man who personally absorbed and carried the crushing pain of hundreds of thousands of individuals who sought him out for healing, comfort, love, acceptance, help and, sometimes, simply a reason to live.

And finally, they are the working principles of a man who made an active choice to consciously curate a philosophy and habits of thought, speech, and action — firmly rooted in 3,000 years of Jewish wisdom, understanding and knowledge that all coalesce into what we refer to in the book as the Rebbe’s “Positivity Bias.”

In Positivity Bias, we learn that positive perception is applicable and accessible to all; that it derives from objective, rational insight, not subjective, wishful imagination, and that positive living is a matter of choice, not circumstance.

Rabbi Mendel Kalmenson is the rabbi of Chabad Belgravia in London. This is an extract from his new book, Positivity Bias, Ezra, £17