Power is the ability for humans to do what we want and accomplish our aims. Power lets us make things happen; power lets us have more control over the future.
Power can be used to accomplish good things, or bad things.
Many fear power. For those who hate power over nature I have little sympathy. Why should we not understand the physics of our world and live effectively? Even walking around, and balancing, are a matter of skillful control over the natural world. Electricity and computers, while considered more unnatural than the power of walking, are also immensely valuable; they transform the world much more to our liking. Some complain that we interfere in the natural order of things. This is magical thinking. There is no natural order. There are just the laws of physics, and the species that happened to evolve here. There is no thought or preference behind it. (It is ironic that people of this sort are frequently atheists who look down on religion.) But never mind that: how best to save as many species as possible, and increase biodiversity? Through skillful manipulation of the natural world for that aim.
Consider five possible worlds:
In one humans commit mass suicide to avoid messing up the natural world. A few millenia later a meteorite wipes out most species, like we suspect happened with the dinosaurs. A few billion years later the sun goes super nova and that's the end. In the mean time, species sometimes die out due to natural variance in climate and other randomness. This future is no good.
In another we continue with somewhat clumsy use of the natural world, and refrain from increasing our power and skill because people fear it will be used badly. We still die to the meteor or at least to the sun. We save some species, but we kill others by accident. This future is no good.
In another we gain great power and control, and we save every species that we want to, deflect meteors, and either change the sun or, perhaps, eventually leave. When we leave we will bring with us any species we wish. Without this gift of space flight they could not survive further. This is paradise.
In another we gain great power and control, but they are used in ways you do not like today. The reason is that your present ideas about what should be done are mistaken. But this is a good future as well. We cannot judge the future by how well it conforms to what we want now. We must judge instead by how rational it is. If it is an open society which favors persuasion then we should be pleased. And if, in the event, we still don't like a policy (in most cases we ourselves would have changed our mind by then) we are free to criticize the mainstream idea and persuade people of our view. And further, in a free society, remember that we can, personally, save all the species we like. The only obstacle is our own personal power. If we have enough control over our world, including the required resources, then we don't need anyone to agree with us. (We may need people to trade with us, and to work for us. But the market allows cooperation without agreement over the proper aims of life, so that is no obstacle.) This, too, is paradise.
In another we have power but people take control of society forcefully and decisions are made by whim not reason. The rulers suppress the power of others. Eventually they start killing people (and they care even less for other species). If you have trouble imagining a suitably dark continuation from there, try reading 1984. This is a disaster by all accounts; this future is no good.
How is this disaster to be avoided? Two main ideas are:
1) Avoiding disaster is a matter of power: skillful control over our lives and our future. With power comes the ability to create safeguards and take steps to prevent disaster. Today we have only limited power to prevent disaster. But if we become more powerful, our power to make the world safe and free will grow.
2) Avoiding disaster is a matter of controlling those who might do ill; the enemy here is freedom. Only people with appropriate, well-liked ideas should be allowed their liberty. Power must be doled out in accordance with who has humanity's best interests are heart.
While certainly there is some danger to (1), it is the only reasonable way to proceed. Yes, we might develop weapons and dangers faster than safety measures. But that is a somewhat strange fear. There is no particular reason that should happen. Meanwhile there are very powerful reasons the opposite should happen: we will develop precautions first because we know to do otherwise is dangerous. Developing dangers we cannot handle is stupid; people will aim to avoid such folly.
You may think the history of war contradicts me. I disagree. Developing powerful weapons provides safety from external invasion (a serious threat). It is true that many societies have been war like. But what of it? We now have an open society and we prefer peace. Our development of powerful weapons technology, like nuclear weapons, was an important part of the defense of our society. And now we have voluntarily ceased development of those weapons. We only wish to have that power to the extent we need it and no more.
Now let's look at (2). There is something implicit in this: there are rulers deciding who to dole out power to, and deciding who has humanity's best interests at heart and so on. And these rulers use force. For our benefit, they say. Remember what we are trying to avoid: people who use force to gain rulership, and who then suppress the power of those they disagree with or otherwise dislike. Well, that is exactly what (2) proposes to set up. Why, then, might it sound appealing? If it sounds appealing probably you are thinking of the disaster as the ascent of bad rulers with bad ideas who hate freedom, and the solution as rulers who like freedom. You identify with the second set of rulers. You imagine they would rule as you would rule. They will promote the values you agree with.
This is a mistake. Even if the rulers start with your values, they might change their minds, or you might change your mind, and then you will not be happy as you find force used against you. And even if you continue to agree that does not mean you are right; we need a society that seeks the truth and creates knowledge. That means an open society with freedom of thought and in which no particular view is entrenched in power.