John C. Bogle is the founder and retired CEO of The Vanguard Group, the largest mutual-fund organization in the world, with more than 160 mutual funds and current assets totaling more than $1.4 trillion. Since his retirement from Vanguard in 1996, Bogle has spent his time studying, writing, and speaking on the financial markets and mutual funds. He is president of the Bogle Financial Markets Research Center, created in 2000 to support his ongoing work on behalf of investors.

In this video segment, Bogle shares his views on optimism in the face of adversity and mentions the many projects he's been involved with recently, including upcoming articles in The Journal of Portfolio Management and the Financial Analysts Journal.

Tom Gardner: My final question: How are you spending your time now? An incredible part of your story -- which we haven't talked about here but we've talked about on the radio -- is your human heart. How old is your heart right now?

Jack Bogle: Well, I got my heart when it was 26 and I've had it for almost 18 years.

Gardner: A year younger than I am.

Bogle: Forty-two. But I'm starting to feel a little more like 84. The trail in recent years has been a little difficult -- the physical trail. I've had some very profoundly serious problems and long hospitalizations, but you go into them optimistically. My wife is a powerful support, and my kids are wonderful. You get over the bumps. You're always optimistic.

The idea when you go into a hospital again is they put you down on the gurney and you just go, "Here we go again." Like the whole business with the transplant, my reaction is just the same, Tom.

If I thought jumping up and down on the kitchen table and screaming and yelling about the unfairness of life would help my condition, I would do it! But it occurs to me it would make it even worse. So you kind of go along. You speak out with honesty. I'm not trying to say something to hurt somebody, but I'm not going to agree with something I don't agree with. I think Vanguard benefits from that immensely.

The shareholders -- I'm still close to a lot of them. I still get a lot of correspondence. I'm still writing a lot. I have an article about to come out in The Journal of Portfolio Management, another article about to come out in the Financial Analysts Journal, a foreword to a book about Paul Cabot, one of the founders of the industry, and a book about John Maynard Keynes published by, I think, Oxford University Press, in which I write the final chapter, called "Adam Smith and Capitalism." And I did a foreword for John Wasik's book on John Maynard Keynes as an investor.

So, I've got Keynes. I've got Adam Smith. I've got one of the industry's founders, and I've got two academic articles, and I'm starting to worry that I'm going to run out of things to do.

Gardner: I don't think that's possible, Jack! Any time you need any extra work that you'd want to do, just come hang out with Fools.

Bogle: OK. Well, you've been a good Fool, Tom.

Gardner: Well, it all started with "Bogle's Folly."

Bogle: We're associated.

Gardner: We're bound by name. Jack Bogle. Thank you so much for taking time. We could continue this conversation for another hour, but let's let you get on with your day.

Bogle: But we tire.

Gardner: Thanks, Jack.

Bogle: Thanks, Tom, very much.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool’s board of directors. Tom Gardner owns shares of Chipotle Mexican Grill and Whole Foods Market. The Motley Fool recommends Chipotle Mexican Grill, Costco Wholesale, and Whole Foods Market. The Motley Fool owns shares of Chipotle Mexican Grill, Costco Wholesale, and Whole Foods Market. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.