It was a sad day in the entertainment world when actor Michael J. Fox, best known for his roles as young Republican Alex P. Keaton on "Family Ties," Marty McFly in "Back to the Future," and deputy mayor Mike Flaherty on "Spin City," publicly announced in 1998 that he had the degenerative brain disease, Parkinson's.

Since then, Fox has become a tireless advocate for Parkinson's disease research through the Michael J. Fox Foundation. But he doesn't let his disease get in the way of seeing "the possibilities in everything." He just published a new book, "Always Looking Up: The Adventures of an Incurable Optimist" and plays a guest role in the FX series "Rescue Me."

He recently spoke with Beliefnet Entertainment Editor Dena Ross about what inspires him.

What has been the most difficult part of battling Parkinson's disease--the physical challenges, emotional, spiritual?

For the last 15 years or so, it's been physical. I mean, the first part of the battle was the emotional, spiritual, and to an extent, intellectual.But, having done a lot of that work early on and getting through that battle, it put me in a place where now I just focus on the physical. The physical are daily battles. But, having done the previous work, I feel sufficiently armed to deal with it.

In your new book you write that your experience with alcohol and Parkinson's led you to look at life in a more spiritual way. How so?

I started drinking more to deal with the Parkinson's when I was first diagnosed. I don't know which came first. I'm trying to think which came first, the chicken or the egg. With the alcohol what you deal with is that you don't have any control over it, that you don't have power over it—that it's more powerful than you in a way. It's gonna do what it's gonna do and you can't stop it. And so, you have to kind of surrender and give up the battle and say "I can't control this. I can't drink in a way that's safe. It's just too powerful for me."

With Parkinson's, it's the same thing. I don't control it. I don't have power over it, so I have to just accept it and then I can move on from there.

I often say now I don't have any choice whether or not I have Parkinson's, but surrounding that non-choice is a million other choices that I can make. And given that the Parkinson's put me in a place I didn't think I'd be, these are not choices that I normally would have at my disposal. These are new choices and they lead to amazing places.

Do you believe in God or a higher power?

I definitely believe in a higher power. If you, for example, say that alcohol is more powerful than you, then there's a greater power than you, a power greater than yourself. I mean, I'm not gonna live in a world where the only higher power than me is alcohol. There's another higher power than that. I don't subscribe to any particular orthodoxy, so I don't define it and I don't put it into a definition that other people have to conform to. An expression I always use is, there is a God and it's not me.

When you were first diagnosed, did you have a moment where you asked, "Why me?"

No, I didn't get into the "Why me?" I got into the "It can't be." I got right into "This is a mistake" and "Can somebody just point out the mistake that's been made here so I can get on with my life?" So that was why a lot of it, for me, was accepting and acknowledging the truth of it.

How do you think you helped yourself accept the diagnosis?

I think it is humility and saying "I can't negotiate this. I can't use who I am in the world to get out from under this." Humility is always a good thing. It's always a good thing to be humbled by circumstances so you can then come from a sincere place to try to deal with them.

Once I started to calm everything down, it was just living with the diagnosis and then allowing myself to accept and educate myself about it. I [spoke] to doctors and scientists, and then also concentrated on my family and realized that I didn't have to fear the effect on them. I kind of projected all my worries onto them and thought they must have the same doubts or the same concerns that I had--without giving them a chance to tell me how they really felt. And when I did, they were great. I mean, [my wife] Tracy was unbelievable. But my first assumption was who'd want to deal with this if they didn't have to?

How do you stay so optimistic?

Well, because the world is just so full of possibilities. I was in Mexico a couple of years ago, and we were hiking on a trail on the Yucatan Peninsula. We had a guide, and he showed us this tree on one side of the path that had this red sap. And he said, "If you see this sap, this tree, don't touch it because it'll burn you. It's really caustic and it's acidic and it'll burn your flesh." And then we walked a little bit further down the trail, and there was a tree on the other side that was a black tree and had a black tar. And he said, "This tar heals burns."