Interviewer: It is now a well-known story that Mr. Tanaka's great achievement was born from a failure. Everybody make mistakes, but how can it be combined with a great discovery?

Tanaka: Well...First of all, you will never find anything new by building up common knowledge. A new discovery is generated from something which seemed to be vain efforts. A failure is just one of those actions. For instance, I mixed ingredients which had been considered useless to mix. If I had just applied the standards of common sense, I might have thrown them away. So why did I mix the ingredients? Probably it's because I had the room in my heart to try. As a Nobel Museum professor mentioned, I had such a playful mind.

Okada: I am sure it's patience that we need to make a discovery. Biological experiments are different from physical or chemical ones. We need some time to even know whether the experiment was successful or not. Be persistent. It's the only way.

Tanaka: Yes, persistence is a must. I failed for weeks and months before I succeeded in making an ion. Why did I continue the experiment? Because I enjoyed it. It was fun for me to come to know something that I had never known before, and that fun enabled me to be persistent.

Interviewer: Mr. Okada, Your research also needs the same persistence, doesn't it? 　

Okada: Exactly. I do my experiments in a really traditional way, just cultivating cells in Petri dishes. I observe them day after day, absolutely expecting that an extraordinary change would happen sometime. Fortunately, I found a cell that began to show a dramatic change one day, just as I had expected.

Interviewer: When you made the famous mistake of mixing metal powder and glycerin, your colleagues told you the output data might just be noise, didn't they?

Tanaka: It didn't seem to me to be a noise because, by repetitive observation, I had naturally acquired an ability to distinguish a subtle difference among the data. I showed my colleagues only one of the data. If you gave me one datum and asked me to explain the difference, I couldn't do that either. It was good for me to keep watching the data as usual.

Okada: Just after finding a cell that changed into a totally different substance in the test tube, I had an opportunity to give a lecture in the U.S. There, I was asked about my motivation to culture cells, waiting for 40 to 50 days for a change. I neatly answered that it was my belief that a cell would transform itself into another substance. But your belief should be made from your studies after all.

Tanaka: When it comes to belief, I also expected the ideal form (of the data) in some senses. While noises appeared so messily, I was waiting for some signals to show up. That's why I could see a signal when it actually appeared.