Twain makes some good points confirming what I believe: that man is simply a biological machine with no free will. That being said, his arguments are opposed by a strawman antagonist who presents examples that are easily defeated. I know this is just a device to further explain and possibly represent a skeptical reader, but at the same time I wasn't convinced it was originating a truly differing perspective. Twain also misses some points.

Yes everyone acts in accordance with their own moral compass bestowed upon them from their environment and genetics. They do things for their own gain first. Does that mean no one contributes? Not at all. Just because you do not originate an idea doesn't mean that your actions are worthless. Yes you're a machine but you're a gear in the complex machine of society, fulfilling your role, for better or worse. Our perceptive consciousness is just along for the ride.

A solider craves praise and a young boy avoids punishment. These are societal mechanisms that ensure the continuation of the species. It's not something to gawk at or be astonished by.

"You don't want the thing. You want the satisfaction the thing brings you". Well, that's obvious. When I'm playing the board game Monopoly, I want the monopoly money because it has value while I play. After the game is over, the money is worthless. Why this factoid would astonish anyone is beyond me.

It's a decent read for anyone curious about free will but too much of the unanswered questions about existence are answered by the God solution which I can't agree with. Some of the points he makes ramble on as well, but I'd recommend it