A year ago tomorrow, I was released from more than two months of secret detention. Police told me today that they have lifted my bail conditions. I am happy that the year is up, but also feel sorry about it. I have no sense of why I lost my freedom and if you don't know how you lost something, how can you protect it?

"Wei" means "future" and also "uncertainty", and the future really is unknown. They have said I cannot leave China because they are still investigating cases against me – for pornography, exchanging foreign currency and bigamy. It is very, very strange. I am not a criminal. They grabbed something from me because they have power.

The 81 days of detention were a nightmare. I am not unique: this has happened to many people, and is still happening. It's an experience no one should share. They were extreme conditions, created by a system that thinks it is above the law, and has become a kind of monstrous machine. Everybody who has been through it loses their original hope or has it changed somehow.

There are so many moments when you feel desperate and hopeless and you feel that's the end of it. But still, the next morning, you wake up, you hear the birds singing and the wind blows. You have to ask yourself: can you afford to give up the fight for freedom of expression or human dignity? As an artist, this is an essential value that can never be given up.

I often ask myself if I am afraid of being detained again. My inner voice says I am not. I love freedom, like anybody; maybe more than most people. But it is such a tragedy if you live your life in fear. That's worse than actually losing your freedom.

What I gained from the experience is a much stronger sense of responsibility, and an understanding of what the problems are and how one can understand what's happening and remain a positive force. You have to see your own position from the other side. At the same time you have to maintain a passion for what you are doing. You have to have sensitivity and joy. If you don't have that, you will be like a fish on the beach, drying up on the sand.

My involvement in so-called political affairs started in 2008. After I designed the Olympic stadium I realised the Olympics was not going to bring real joy to society but propaganda. I stood up and criticised it. I'd already become active on the internet and every day I would see so many problems. I started to write about judicial procedures and we started to make documentaries, including one about the children who died in schools that collapsed in the Sichuan earthquake. I gained support among young people and people on the net and I think that made the government scared.

I started to ask: why can't they solve minor problems rather than have them blow up? Of course, no one is listening. You talk to the wall and the stones. Every time you try to correct something, or demand a clear answer, your situation becomes more miserable.

They destroyed my studio, they put me in secret detention and they fabricated a crime that put a 15m yuan tax bill on me. We are now suing the Beijing tax authorities for abuse of powers and ignoring procedures. We are using this opportunity to make them realise what's wrong and inform the public, even though we know the results won't be positive. They refused to give us our papers back or let our manager and accountant be witnesses at the trial on Wednesday, or let me attend court. They even made my friend Liu Xiaoyuan, a lawyer, disappear before the hearing.

Friends of mine say: "Weiwei, my father has been questioned, my mother has been questioned, my sister has been questioned because of you." I don't know these people. Why does the system make them suffer? Because it can't allow anybody to exercise their humanity and communicate or show support. But when your children are growing up and will never have a chance to have their voices heard, do you want to turn your face away and say OK, that's not my problem?

Reflect on Bo Xilai's case, Chen Guangcheng's and mine. We are three very different examples: you can be a high party member or a humble fighter for rights or a recognised artist. The situations are completely different but we all have one thing in common: none of us have been dealt with through fair play, open trials and open discussion. China has not established the rule of law and if there is a power above the law there is no social justice. Everybody can be subjected to harm.

I'm just a citizen: my life is equal in value to any other. But I'm thankful that when I lost my freedom so many people shared feelings and put such touching effort into helping me. It gives me hope: Stupidity can win for a moment, but it can never really succeed because the nature of humans is to seek freedom. They can delay that freedom but they can't stop it.

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