In his profiles on social media, Paul Allen describes himself as a “philanthropist, investor, entrepreneur, Seahawks and Blazers team owner, guitarist, neuroscience supporter, space pioneer & Microsoft co-founder.”

The order is significant. Over the past 20 years, the 62-year-old has become one of America’s most generous billionaires, giving away more than $2 billion to 1,500 nonprofits focusing on everything from wildlife conservation to a pop-culture museum.

Of all his causes, Allen’s dual efforts to reverse-engineer the human brain and build one from scratch through artificial intelligence are arguably his most ambitious.

Allen said his hope is to understand “what makes humans different from other animals and how evolution happened.”

This interview has been edited for length and clarity.

When it comes to science, how do you determine what kinds of projects to fund? Can you describe the process you go through when exploring potential areas of research to invest in?

I just try to stuff my brain with everything that I can read on what is going on in science at a very high level, and sometimes I see connections of what might need to be done. Or someone makes a suggestion, and I latch on to that and whenever something crystallizes I explore it further.

These days, I pretty much go through Allan Jones and Christof Koch and Clay Reid [at the Allen Institute]. If I find an article that is interesting and if that resonates with them, we’ll put together a brainstorming effort and find a dozen people that are the top people in the world, and then get some of them to come in. We’ll ask: “What is a more fertile area to pursue? Where can we start to get traction?” You have to winnow the problem down.

It’s always interesting to bring scientists together, because they typically have very polarized views. Usually, we have a couple of days at a retreat at a hotel or at a place I have in the islands. The one we had on cell biology, we just had a big meeting room and sat around at a table and had debates. Then you try to form a consensus for an approach to a particular problem, and once you pick the system you are going to attack, you put together a plan. It’s a very iterative process.

In fact, you recently had a dinner with a group of brain scientists. What was the most interesting takeaway?

We talked about sleep for half an hour. No one knows the complete function of sleep. Is it to reset the brain or give it more of a rest period? Is it for cleaning the brain of all the garbage protein? For me, talking about these things as a non-biologist is fascinating.

What other science-related things are you thinking about these days?

I am generally fascinated by what are the big challenging questions — that’s behind my curiosity. I was fortunate enough last summer to go to Greenland and see the glaciers and literally watch global warming happening. You see the ice cap melting and you know just how much we are in trouble.

Last year, President Obama announced a very ambitious and possibly very expensive national effort to advance brain research. What do you think of this?

It’s very encouraging for me. If you look at the Human Genome Project, the government did this in a very similar way with great impact. There are other projects, in other areas of science, that everyone agrees you need to move the field forward, like the Large [Hadron] Collider in Geneva for physics. In biology, that hasn’t been the case — until now. I’m happy to be helping get it done. The more people that are engaged, the better.

What advice do you have for the younger generation of billionaires just starting out with philanthropy?

Try to figure out what causes you are passionate about. My friend Bill [Gates] and his wife, Melinda, have invested so much effort in global health because they believe in it. Know you can make a difference in the progress of humanity or make humanity better.

How did this approach to philanthropy lead you to fund brain science?

As someone who was basically a software engineer for many years, I became fascinated with how the brain functions and is put together and works in such a different fashion than computers do. Computers are really basically computing elements and a lot of memory. They are pretty easy to understand, as compared to the brain, which was designed by evolution. Every little bit is different.

[My mother’s Alzheimer’s] deepened all my motivations to want to bring forward treatments for the different pathologies of the brain that can develop: Alzheimer’s, Parkinson’s and many other brain diseases. They are horrific to watch ­progress. Anything that could bring forward treatments is heartening for everyone that is affected and their families.

The Allen Institute for Artificial Intelligence, or AI2, just launched in 2014. What can you tell us about AI2’s mission?

We’re going to take a clean sheet of paper and try to create from scratch what we think is an interesting way to approach the understanding of knowledge and how knowledge and language interact. I was recently able to bring on Oren Etzioni from the University of Washington.

If you saw the development of Watson, you saw it was very successful at beating human competitors on very superficial questions. Imagine in our case we’re trying to encode a piece of software that could answer questions about all knowledge. These are some of the toughest questions we have. . . . and I feel very blessed to be able to try to move the field forward.

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