Even when I was studying mathematics, physics, and computer science, it always seemed that the problem of consciousness was about the most interesting problem out there for science to come to grips with.

Although I'm Australian, I find myself much more in sympathy with the Austrian version!

Many people and governments share the mistaken belief that science, with new, ingenious devices and techniques, can rescue us from the troubles we face without our having to mend our ways and change our patterns of activity. This is not so.

Scientific facts are often described in textbooks as if they just sort of exist, like nickels someone picked up on the street. But science at the cutting edge, conducted by sharp minds probing deep into nature, is not about self-evident facts. It is about mystery and not knowing. It is about taking huge risks.

I happen to love science... Scientists are all slightly mad. There is truth in the stereotype of the mad scientist. They are mad with curiosity.

No one knows exactly when or where the redwood entered the history of life on earth, though it is an ancient kind of tree and has come down to our world as an inheritance out of deep time.

We're creating these massive urban areas in the Third World. It's like you take the entire population of California and put it in one city. Then you remove basic sanitation and medical services, and you have a ticking biological time bomb.

Experiments suggest that if one particle of Ebola enters a person's bloodstream, it can cause a fatal infection. This may explain why many of the medical workers who came down with Ebola couldn't remember making any mistakes that might have exposed them.

If a vaccine works, then the vaccinators might conceivably set up what's known as ring vaccinations around Ebola hot spots. In this technique, medical workers simply vaccinate everybody in a ring, miles deep, around a focus of a virus.

Redwood time moves at a more stately pace than human time. To us, when we look at a redwood tree, it seems to be motionless and still, and yet redwoods are constantly in motion, moving upward into space, articulating themselves and filling redwood space over redwood time, over thousands of years.

Anyone who attempts to generate random numbers by deterministic means is, of course, living in a state of sin.

I combine magic and science to create illusions. I work with new media and interactive technologies, things like artificial intelligence or computer vision, and integrate them in my magic.

This is a really big space station. We do a lot of various kinds of work here, different kinds of science experiments; we have over 400 different experiments going on at any one time in different areas, from basic science research to medical technology, that hopefully will benefit more people on Earth.

It's a combination of science, maintenance, and general housekeeping. And then, occasionally, robotics activities or a spacewalk you might get to do.

There's a lot of work to do - not only the science but maintaining the facilities up here. When you go down from a crew of six to a crew of three, obviously you've lost half of your crew time available, so it does have an impact. But it's an impact we plan for.

I went to the University of Maryland for a year and was considering maybe, you know, being a medical doctor but decided my other interest was maybe flying airplanes in the Navy and just kind of changed my mind and changed schools and changed majors and decided to focus a hundred percent on that.

What we look for are people that are technically competent. You need a background in a scientific field, whether it's as a scientist, an engineer, medical doctor, or, you know, a person that's in the military with some kind of technical background.

People do really well on space missions, but it's the physiological, the medical stuff, the stuff like radiation, loss of bone mass and muscle mass and density. It's those things that we need to figure out.

It's an international space station. We have crew members from both the U.S. and Russia and now the United Kingdom with Tim Peake from the U.K... It's great to see that, on this space station, that we can work across cultures in a very cooperative way.

Just like the bones and muscles, the heart is designed to work in one gravity here on Earth, so when you put the heart in space, it operates differently and changes shape.

This year-in-space mission was a profound challenge for all involved, and it gave me a unique perspective and a lot of time to reflect on what my next step should be on our continued journey to help further our capabilities in space and on Earth.

When I look at the clouds over the Earth, and I know how high clouds are, I get a sense we are really, really far above those clouds. I wouldn't call it scary, but I am aware I am in space.

We don't do laundry because that requires a lot of water, and water's at a premium up here. Plus, it'd be pretty complicated, I think, to make a space washer, although I guess you could do it.

I don't think people have an appreciation for the work that it takes to pull these missions off, like humans living on the space station continuously for 15 years. It is a huge army of hard-working people to make it happen.

The Earth is a beautiful planet. The space station is a great vantage point to observe it and share our planet in pictures. It makes you more of an environmentalist.

The ride to orbit was impressive, as it always is. But once I got on board the space station, it really felt like I was visiting an old home; it felt very comfortable.

Your arms don't hang by your side in space like they do on Earth because there is no gravity. It feels awkward to have them floating in front of me.

Sleeping here is harder here in space than on a bed because the sleep position here is the same position throughout the day. You don't ever get that sense of gratifying relaxation here that you do on Earth after a long day at work.

I believe in exploration, and I will miss being on the front lines of that endeavor. On one hand, I look forward to going home, but it's something that's been a big part of my life, and I'm going to miss it.

Facts are not science - as the dictionary is not literature.

Half of the modern drugs could well be thrown out of the window, except that the birds might eat them.

Knowledge is a process of piling up facts; wisdom lies in their simplification.

A good teacher must know the rules; a good pupil, the exceptions.

Whenever ideas fail, men invent words.

In the sick room, ten cents' worth of human understanding equals ten dollars' worth of medical science.

In the U.S. you have a system of lobbying and influence on our policy and law makers which is incredibly pronounced. The gas industry spent $250 million getting an exemption from our Safe Water Act. Every one of those dollars is toxic; a contaminant in our political system. It disrupts the normal flow of justice, science, fact and reporting.

The problem is that everywhere the gas drilling industry goes, a trail of water contamination, air pollution, health concerns and betrayal of basic American civic and community values follows.

The Safe Drinking Water Act, the safety provisions of the Clean Water Acts, the Clean Air Act, the Superfund Law - the gas industry is exempt from all these basic environmental and worker protections. They don't have to disclose the chemicals they use. They don't have to play by the same rules as anybody else.

The BP spill was the greatest environmental catastrophe in U.S. history. Yet somehow, gas companies like BP and Halliburton ran interference on reporting that story.

Ambiguity is very interesting in writing; it's not very interesting in science.

We have never observed infinity in nature. Whenever you have infinities in a theory, that's where the theory fails as a description of nature. And if space was born in the Big Bang, yet is infinite now, we are forced to believe that it's instantaneously, infinitely big. It seems absurd.

It is this conception of the unity of the human career which is perhaps the greatest achievement of historical study, since it gained a place analogous to that of natural science.

They have seized upon the government by bribery and corruption. They have made speculation and public robbery a science. They have loaded the nation, the state, the county, and the city with debt.

California must be all American or all Chinese. We are resolved that it shall be American, and are prepared to make it so. May we not rely upon your sympathy and assistance?

Science and policy-making thrive on challenge and questioning; they are vital to the health of inquiry and democracy.

Meat is a wasteful use of water and creates a lot of greenhouse gases. It puts enormous pressure on the world's resources. A vegetarian diet is better.

A diet that relies heavily on meat production results in higher emissions than a typical vegetarian diet. Different individuals will make different choices. However, the debate about climate change should not be dumbed down to a single slogan, such as 'give up meat to save the planet.'

I think that once people understand the great risks that climate change poses, they will naturally want to choose products and services that cause little or no emissions of greenhouse gases, which means 'low-carbon consumption.' This will apply across the board, including electricity, heating, transport and food.

In science, technology, engineering and mathematics, men far outnumber women in the classroom and the boardroom.

Technology is one of the key drivers of female economic empowerment, but the fields that women choose to participate in are still decidedly gendered.