Dr Pascal de la Croix, a French robotics professor who is currently based at MIT, was one of the few people Hiro Yanagida’s father, renowned robotics expert Kenji Yanagida, agreed to talk to in the weeks following the crash that took his wife’s life.

I have known Kenji for years. We met at the 2005 Tokyo World Exposition when he unveiled the Surrabot #1–his first android doppelgänger. I was immediately captivated–what skill! Although the Surrabot #1 was an early model, even then you could barely tell Kenji and it apart. Many people in our field dismissed his work as narcissistic or fanciful, scoffed at the fact that Kenji’s focus was more on human psychology than robotics, but I did not. Others found the Surrabot #1 deeply disturbing, tapping, as it does, into the uncanny valley inside all of us. I have even heard people say that creating machines that look exactly like human beings is unethical. What nonsense! For, if we can understand and unlock human nature, surely that is the highest calling?

Let me move on. We kept in touch over the years, and in 2008, Kenji, his wife Hiromi and their son came to stay with me in Paris. Hiromi did not speak much English, so communication with her was limited, but my wife was enchanted with Hiro. ‘Japanese babies, so well behaved!’ I think if she could have adopted that child then and there she would have done so!

I happened to be in Tokyo when I heard the news about the plane crash and Kenji’s wife’s demise. I knew immediately that I must go to see him, that he would need his friends more than ever. I had lost my father, you see, a man to whom I had been very close, to cancer the year before, and Kenji had been very kind with his condolences. But Kenji did not answer his phone, and his assistants at the Osaka University would not reveal to me where he was. In the days that followed there were pictures of him everywhere. There was not the media madness that attended the survival of the American boy and the poor child from Britain–the Japanese are not so intrusive–but there was still much attention. And the crazy rumours! The whole of Tokyo appeared to be fascinated by Hiro. I heard tales from the hotel staff that some believed the boy harboured the spirits of all those who had died in the crash. Such nonsense!

I thought of going to the memorial service, but did not think it would be my place to do so. Then I heard that Kenji had returned to Osaka. I decided that instead of returning home, I would make one last attempt to see him, and I booked myself on the next available flight to Osaka. By then, air traffic was almost back to normal.

I am not ashamed to say that I used my reputation to gain entrance into his laboratory at the university. His assistants, many of whom I had met before, were respectful, but told me that he was unavailable.

And then I saw his android. The Surrabot #3. It was sitting in the corner of the room, and a young assistant appeared to be talking to it. I knew immediately that Kenji was talking through it; I had seen him doing this before on many occasions. In fact, if he was asked to go on the lecture circuit and could not leave the university, he would send his robot instead and talk through it remotely!

You want that I should explain a little how the mechanism works? In the most simple language I can use, it is controlled remotely, through a computer. Kenji uses a camera to capture his face and head movements and these are transmitted to servos–little micro-motors–embedded inside the android’s face plate. This is how it mirrors his facial movements–even blinking is replicated. A microphone records Kenji’s voice, and this is conveyed via the android’s mouthpiece, right down to the slightest intonation. There is also a mechanism inside its chest–not unlike those used by high-end sex doll manufacturers–which simulates breathing. It can be most disconcerting talking to the android. At first glance it certainly does look like Kenji. He even changes its hair whenever he has a haircut!

I insisted on speaking to it and said without hesitation, ‘Kenji. I was so sorry to hear about Hiromi. I know what it is you are going through. Please, if there is anything I can do, let me know.’

There was a pause, and then the android said something in Japanese to the assistant. She said to me, ‘Come,’ and told me to follow her. She led me through a bewildering number of corridors, and down towards a basement area. She politely refused to answer any of my questions about Kenji’s well-being, and I could not help but admire her loyalty to him.

She knocked on an unmarked door and it was opened by Kenji himself.

I was shocked when I saw him. After just talking to his android doppelgänger, the fact that he had aged terribly was even more noticeable. His hair was dishevelled and there were dark circles under his eyes. He snapped something at his assistant–which was unlike him, I had never seen him be discourteous before–and she hurried away, leaving us alone.

I gave him my condolences, but he barely seemed to hear them. He kept his features absolutely still; only his eyes showed any sign of life. He thanked me for coming all this way to see him, but said it was not necessary.

I asked him why he was working in the basement and not the lab, and he told me that he was tired of being around people. The press hadn’t stopped harassing him since the memorial service. Then he asked me if I wanted to inspect his latest creation and waved me inside the room.

‘Oh!’ I said, as soon as I stepped inside. ‘I see that your son is visiting you.’

But before I finished the sentence I realised my mistake. The child sitting on the small chair next to one of Kenji’s computers was not human. It was another of his replicas. A surrabot version of his son. ‘Is this your latest project?’ I asked, trying to hide my shock.

For the first time he smiled. ‘No. I made that last year.’ And then he gestured to the far corner of the room where a surrabot dressed in a white kimono was sitting. A female surrabot.

I walked towards her. She was beautiful; perfect, a slight smile on her lips. Her chest rose and fell as if she was breathing in and exhaling deeply.

‘Is that…?’ I could not say it.

‘Yes,’ he said. ‘It is Hiromi, my wife.’ Without taking his eyes off her he said, ‘It is almost as if her soul is still here.’

I attempted to ask why he had felt the need to build a replica of his deceased wife, but the answer is obvious, is it not? He avoided my questions, but he did tell me that Hiro was living in Tokyo with relatives.

I did not say what I was thinking: ‘Kenji, you have a son who is alive. Who needs you. Do not forget this, my friend.’

Not only was this not my business, I knew that his grief ran too deep to listen to what I was saying.

So I did the only thing I could do. I left.

Outside, not even the city’s beauty could calm me. I felt unsettled, as if something in the world’s axis had shifted.

And as I stood, looking back at the university building, it started snowing.