Dave Rogers said some things about what I said about what he said. I agree with his early sentiments. "Freedom" is a complicated concept, and I suspect it's not really worth unraveling, so let’s just work on whatever shared meaning we can squeeze out of that word.
We can know wrong things, and that’s just as — if not more — constraining as not knowing anything. But the only way to find out something we know is wrong is to come to know something right. Learning something wrong is the risk we take when learning. But in my experience, it’s not a very big risk.
Dave asks "how much knowledge you want to have before you think you have enough freedom. At what point does the desire for knowledge itself act as constraint?" I don't know what "enough freedom" would be in the general sense. I’ve never met anyone who didn’t seem to want more freedom.
But in specific contexts, I think "enough freedom" is an important question we all need to answer for ourselves. Some people find alcohol consumption increases their overall freedom, so they seek out knowledge to help increase their freedom to consume alcohol. Personally, I find alcohol consumption reduces my overall freedom, so I seek out other knowledge.
I think knowledge — like everything else, I suppose — acts as a constraint as soon as it becomes its own end. Let’s take an analogy: I’m trapped in a box. I want to get out of the box. You might respond with your transcendal wisdom that "there is no box," but seriously, there is. It’s made of wood, and I’m in it and I’m hungry. Not like "I could really go for a bowl of ice cream" hungry, but real "this hurts" hungry.
So my first step in getting out of the box (gaining freedom) is to learn about the box. I see that the box is nailed shut. This is useful knowledge. I see that there’s a crowbar inside the box. Also useful knowledge. I think to myself "knowledge is so great!" I look around the box for all the knowledge I can find. I inspect every grain in the wood, every curve in the crow bar, every nail in this box holding me in. I love knowledge! And I starve to death in the box, excited at my newfound knowledge of death.
I think that point where I notice the crowbar and start to value knowledge itself rather than the specific knowledge that enables me to increase freedom (using the crowbar to open the box) is where knowledge becomes constraining. Dave writes "Maybe we're all about as free as we're ever going to be." Maybe, but I doubt it, and I hope not. Such a flat world just doesn’t sound like much fun.
At it's essence, freedom is simply one's ability to choose his own path in life. The more knowledge one gains (either of a previously unknown path's existence, or skills required to travel down it), the more paths one has to choose from, and freedom is gained.
We are all born with the freedom to move our bodies as we wish - every bit of knowledge we gain from birth helps us hone our skills and understand the effects of those movements (from speaking to writing to becoming a surgeon). The more we understand of our world, and understand what our actions mean to us (and the world around us) the more freedom we have.