The Scientific Method, which has served humankind so well for the past few centuries, is based on finding and explaining Truth. The knowledge gained from science cannot be restricted, as any restriction would attempt to limit that which is True, which is impossible. The Truth simply exists. Those who would limit (or shall we say repress) the Truth do so for their own agenda, and provide a cultural disservice to us all. If science becomes increasingly politicized (for example, over the issue of global climate change) then yes, we risk the undoing of several centuries of progress as we regress into Scholasticism, where things are true because an authority says it's true; no evidence need be presented. In fact, all evidence will be manipulated or destroyed. Sounding a bit like Orwell's 1984, where the science of Astronomy has been reduced to where the stars are little fires in the atmosphere of Earth.
One could argue that it is not the knowledge itself that causes difficulty--therefore no limit is necessary. One could argue that it is both the interpretation put upon the knowledge (think of the Church against Galileo and Copernicus) and the technology developed from the knowledge (think of atomic bombs, plasticizers and nanotechnology) that causes the trouble. Therefore, by extension of the limitation argument, limits are necessary on interpretations and technology. Limitations on these take the shape of ethics, morality, honesty, the absence of manipulation, the presence of rationality, compassion, valuation of human dignity, guilelessness, etc.
I agree with most of the posts above. We should be very wary of placing limits on scientific knowledge, other than the widely accepted ethical limits that are now in force. For instance, any experiment of any kind that occurs at my university and that involves human or animal subjects must first be approved by a review board and must follow strict ethical guidelines. The same kinds of guidelines are in force today throughout American higher education.
One should remember that during the Middle Ages, scientific knowledge was restricted, as it tended to disagree with scholasticism, which accepted only the Bible and Aristotle as authority. Scholasticism actively discouraged experimentation as it was believed that experimentation led to error, which led to sin. This was a time when those who dared question authority were often burned at the stake, or tortured until they recanted. Galileo himself recanted his findings (at least nominally) when threatened with torture.
If and when we begin to limit scientific knowledge, we have taken a giant step backward to those days when knowledge was considered equivalent to sin. Let us all hope that day never comes.
I agree with others that there should not be limits on scientific knowledge. But it is sometimes hard to disentangle the methods of arriving at that knowledge from the knowledge. What I'm saying is, there are some experiments that are unethical or impractical to carry out. On the ethical side, there are rules put in place to preserve the health and well-being of human and animal subjects in experiments. The Institutional Review Board at colleges and universities, for example, are required to ensure that subjects of studies are treated ethically.
Some kinds of knowledge are simply impractical. Climatologists can gather data, but must use models to predict how climates will behave. One can't so easily just change variables in a region and see what affects it would have on the weather - and I doubt one would want to do that for the likely inadvertent consequences such an experiment would have.
Don't read me as saying we shouldn't study and learn about the universe. I think we should learn all that we can, as much as we can. I'm in favor of robust funding of scientific research in all areas. But there are limits to the way that knowledge can be obtained.
No limits should be placed on knowledge. The critical questions start arising when we begin to examine the potential ethical problems created with some applications of that knowledge. Drawing the limits on how some knowledge is used is a challenge that will continue to cause debate.
I don't think there should be any limits on knowledge. It is the actions taken to get it that worry me. For example, we got a lot of important knowledge from the Nazi experiments, but at what cost? We have to value human life more.
We should not try to limit scientific knowledge in any sense, but we should have some standard of ethics that prevents abuse of science. One limitation that should be in place is the regulation and prevention of pseudo-scientific medical practices, which have been shown over and over to cause more harm than they help. Without standards, anything that cannot be shown to be explicitly harmful 100% of the time is allowable with a disclaimer that "no medical claim is implied or guaranteed," even when the rest of the box makes medical claims left and right.
Another problem is the influence of politics on science. Many research centers are funded by political action groups, causing them to cook data and misinform the public so as to continue their funding. Naturally, in the U.S., each political side accuses the other of causing this bias; I see it on both sides, and linking scientific research to politics is a bad idea. Science cannot afford to become a biased field, or it risks being as subjective as any other.
None. There is no way that we can actually limit scientific knowledge anyway, so why try. It's not like we can tell scientists "don't think about cloning." Or "don't think about chemical weapons." We can avoid funding the creation of some things (clones, chemical weapons, stem cells, depending on your political views) through the government, but there is no need to try to limit what people can research.
Scientific knowledge will grow in every direction because that is what scientists do. There is no way to limit them and, if we tried, we might well cut off directions in research that would actually help us in the long run.
I'm not sure we should ever consider limiting the knowledge that scientists uncover concerning the unknown mysteries of our world and those that we have not yet discovered. Free and imaginative thought should never be discouraged, especially when it comes to scientific advancements that will further modernize and improve the world in which we live.