There's a scene in Eternal Sunshine of the Spotless Mind where Clementine snaps at Joel: 'what's in all those journals if your life is so empty?'

That is similar to a question I've been asked many times by people who have seen my notebooks. They are intense. I fill them in days sometimes. I can sit and scribble for hours, even when there's not a lot going on.

My answer is simple: much more of my life happens internally than externally. My thoughts are just as interesting as events which happen. Maybe you have noticed how few of my essays here are concerned with actual happenings. Most centre around little realisations, conceptions and personal growth. The same is true for my private diaries.

Our internal lives are the worlds within out own minds. The strange thought tangents which will never be shared. The ability to mull over a topic for an hour whilst staring out of a train window. To be content regardless of what is going on around you. It is a Stoic attitude- being impervious to extraneous events and altogether self-contained.

Over time I have realised that happiness is a skill, and creating a rich internal life is perhaps the most secure way to master it. As Marcus Aurelius wrote 2000 years ago, 'it is in your power to retire into yourself whenever you choose.'

As a consequence, it helps to have somewhere interesting to retire to. If we put half as much effort into furnishing our minds as we do our homes, the world would be a much happier place. It is our own inflated sense that the world owes us happiness which creates this widespread misery.

To learn anything, it is often helpful to look at those who have done it in extreme circumstances. Just like athletes training at high altitudes, a lot can be learned from those who found happiness in difficult circumstances. There is little use in looking at the privileged, pampered people who flaunt their shallow displays of pleasure which get mistaken for happiness. These are not helpful role models.

Some examples which I return to endlessly include Jean-Dominique Bauby when he was paralysed, Patti Smith in the early New York days, Seneca in exile, Marcus Aurelius in general, Murakami during long distance running.

To look at how those people managed to sprint at high altitudes makes my sea-level jog seem easy. As I have poured over each of their writings, I have found that they all had the ability to find the calm within the storm. The means to find comfort and security within their own thoughts. The capacity to rise above everything to some higher level of consciousness.

Advice is autobiography. I am writing this as much because I need to crystallise my thoughts as because I think anyone else might. These are some of the things which have helped me to handle both depression and difficult circumstances.

1. Read a lot and read challenging stuff.

Books are more than entertainment or even education. Whilst other forms of media certainly have their benefits, reading is an active skill, not a passive one. It enables you to add centuries (if not millennia) of knowledge and experience to your own repertoire. No matter the current situation, a book can always transport you elsewhere. It's a form of cheap, accessible, portable escapism. Truly, I can't think of anything better.

In Just Kids, Patti Smith explains how her battered copy of Illuminations by Rimbaud guided her:

"My unrequited love for him was as real to me as anything I had experienced [...] it was for him that I wrote and dreamed[ … ]his hands had chiselled a manual of heaven and I held them fast."

Through poverty, the death of friends, personal crises and artistic strife, Patti followed the path that Rimbaud he laid out for her. He was her guiding light, a source of security. Rimbaud himself doubtless followed a path laid out by those who came before him. And so on, ad infinitum.

The happiest people are those who read because they live many different lives. Think of Malcolm X and how he turned a prison sentence into his personal heaven by spending every minute of the day reading. An otherwise appalling situation became a blessing for him, because he turned his own mind into an impenetrable fortress, making him impervious to the frustration which ate up others around him.

2. Get used to spending time alone and being independent.

Seneca reminds us that ‘nothing is better proof of a well-ordered mind than a man’s ability to stop where he is and pass some time in his own company.’

There is no point in nurturing a mind which is never retreated into. Few people would turn down an invitation because they have scheduled time with themselves. Few people feel comfortable going to a restaurant or on holiday alone. Few people have a sense of their identity which is not predicated on their social standing. It is what Charles Cooley called ‘the looking glass self’- we see ourselves how we imagine others see us. So we build our lives around external relationships.

Sure, being social is a natural instinct. Family and friends have been consistently shown to be vital components of happiness- perhaps even the most important element. But that need not detract from this vital part of building a rich internal life. Getting used to being independent at times requires the ability to comfort, discipline, inspire, educate and entertain yourself.

3. Build an internal locus of control.

Relationships are transitory. Few people keep the same friends or partner throughout their entire life. Careers and businesses can fail. Skills become outdated. Money can be lost or rendered obsolete. As Marcus Aurelius writes, 'the memory of everything is very soon overwhelmed in time.'

Instead of placing the blame on other people, we can look inwards. Not with the intent to find fault with ourselves (although that is where it all too often lies) but to find the calm there. This is not some hippy-dippy faux zen crap. This is about having a solid sense of self and the ability to control our god damn minds. Rather than being, as Marcus Aurelius put it, tugged around like puppets.

In short, we must understand that we have more power over our minds and lives than we think. There is no grand system holding certain people back. It is not the fault of the stars, the weather, your parents, some politician.

4. Find focus.

When things are bad, it is easy to let your thoughts spiral uncontrollably. Rumination is a survival instinct- when a physical threat is looming, it is a good idea to keep it in mind.

This is a good skill to develop as the ultimate form of self-reliance. It means controlling your own thoughts and not getting wrapped up in negative spirals. It means discipline in regards to doing stuff no one is forcing you to do. It means choosing what you want to think about at any particular time.

5. Recognise that the current moment is nothing special

Tony Robbins gave a recent interview where he said that investing is 80% psychological warfare. Looking at history, the stock market has consistently crashed every single year. Always. Yet each time it happens, some people freak out and lose vast sums of money. Meanwhile, the smart people take advantage of that and wind up richer. In essence, history repeats itself and it would do us good to understand that, as Thomas Nagel said, the present is merely one time amongst others. Everything which happens has happened to countless people before.

Before the advent of the printing press, scholars regarded a text as more trustworthy the older it was. Why? Because knowledge was passed on verbally before it could be written, meaning it degraded over time. Older texts were consequently more accurate. The same still stands. We can learn far more about politics, psychology, power and love from ancient texts than we can from most modern ones. If it has survived that long, it must resound universally. Not to say that modern writing is not worth reading, but that it takes time for the cream to rise to the top. 99% of books will be forgotten within a few years. Only the absolute best will last a decade, let alone a century or millennia.

Think of the tralfaladorians in Slaughterhouse 5. They are aliens for whom all time occurs at once- everything that will happen has happened and everything that has happened is happening now. In our internal worlds, we can acknowledge that and be impervious to the present. We can now that we are merely witnessing a rerun, and act accordingly.

6. Forget about goals, focus on habits.

Getting what we want the most rarely makes us happier. Research has shown that when a person visualises a goal too many times, their brain begins to see it as already completed. As a result, their motivation wanes and the actual achievement falls flat.

Why does Stephen King still write every day? Why does Paul McCartney still sing every day? Why does Yayoi Kusama still paint every day? Why does Warren Buffet still research every day?

Because they have to. Each has turned their craft into a habit. More than that, they have made it part of the very fabric of their being. In short, there has never been an end goal for them. It was never about reaching a certain income or degree of fame. It was simply about the act of just doing - singing, painting, writing, investing, whatever. Maintaining that attitude of continuous learning and self-improvement turns their craft into a lifelong process of getting better by increments.

Doing so creates self-containment. It enables us to direct our thoughts towards the necessary repeated actions, day by day. Most people focus on the dramatic breakthroughs when the real work is done in our internal worlds as we repeat the minute actions necessary to get somewhere. This cannot be faked, or hacked, or cheated at. It is the slow process of creating the discipline within our own minds to ensure we need not rely on motivation or sudden flashes of inspiration.

As Peter Singer wrote in Practical Ethics, ‘our own happiness is a byproduct of aiming at something else and is not to be obtained by setting our sights on happiness alone.’