Well, of course this thread has nothing to do with the title, big surprise. You guys push sugar like freakin' drug dealers.
Cravings are unnatural emotional responses. There are a couple of illegal drugs that I love. Should I give in to those cravings? But sugar isn't a drug and I'm just nuts. Except that to anyone who is 50% or more overweight, I would put forth that maybe sugar is a drug.
As an adult, and someone who has been an adult for longer than a lot of posters have been alive, no one (except the occasional legal entity) forbids me to do or eat anything. I make choices. While it did take a little reading and learning for me to give up all wheat, it wasn't a big part of my diet before I found primal. Nor were beans. White rice I usually ate when I made salmon and I still occasionally eat it when I make salmon because salmon just seems to snuggle so nicely on a bed of white rice. I ate brown rice exactly twice - it tastes like crap and that's not what food should be. And the day I'm in the mood for a baguette and brie in the park, I'll go ahead and eat it.
There's no stress in avoiding cookies. Dark chocolate was my chocolate of choice years before I knew it had some healthy properties. I also don't agree that wine is that great. It's good for cooking, and tastes good along side some foods, but for purity and lack of carbs, I'll choose clear spirits any day. So no primal evangelical here.
What I know for me from experience is that when I tried Atkins years ago, I lost 40 pounds effortlessly and I wan't hungry. That was about 20 carbs per day. For me it wasn't sustainable much past that. Or maybe I just chose to go back to eating bread because I didn't know about the whole wheat thing back then.
So a "caveman" goes out to forage one day and comes upon this grain - let's call it wheat. Since he doesn't know how to process it, he just eats it as food. The next day he wakes up to a loud noise - that would be air escaping his anus. His mate giggles and then laughs even more loudly as he runs outside to take a huge liquid dump behind the nearest tree. Anything anyone eats that comes from wheat is a processed food and our caveman is the reason why. Wheat is for hooved creatures and rats, not for humans (no matter how rat like they may behave).
As for equating a cookie with a piece of fruit, surely you jest. Fruit is what our hypothetical caveman ate when he wanted something sweet, not Mrs. Fields (sorry Debby, I do admire your business acumen totally).
I haven't read up a lot on cancer because (knock on wood) there hasn't been a lot of it in my family, especially the last two generations. And even before that, if someone is 86 and they die of cancer, well, they were going to die of something fairly soon. But if Paleobird says that sugar feeds cancer cells, I would bet your donuts to dollars that she's done the research and isn't just putting out some opinion.
So, to answer the title, no, we can't think like cavemen. We have grocery stores, birth control, and electronic communication, just to name a few things. But we can think intelligently and see that the advice we've been given over the last 30 years has turned us into overweight diabetic allergic asthmatic messes. And the recommendation that we all eat like livestock is probably the most detrimental of all.
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine