The last thing you ever want to do is extend the period of frailty and disability and make people unhealthy for a longer time period. So lifespan extension in and of itself should not be the goal of medicine, nor should it be the goal of public health, nor should it be the goal of aging science.

Once you avoid the things that accelerate aging like smoking, obesity, excessive alcohol consumption, and excessive sun exposure, you've done about as much as you can to influence your aging process.

We have grown accustomed to the wonders of clean water, indoor plumbing, laser surgery, genetic engineering, artificial joints, replacement body parts, and the much longer lives that accompany them. Yet we should remember that the vast majority of humans ever born died before the age of 10 from an infectious disease.

Ageing is very rare. We only see it in humans and laboratory animals and in zoo animals and in our pets. Basically, organisms that are protected from the external world. Once you create that protection, you live long enough to see ageing.

Order is the sanity of the mind, the health of the body, the peace of the city, the security of the state. Like beams in a house or bones to a body, so is order to all things.

If you look at things that really affect people's lives - sport, the arts, charities - they were always at the back of the queue for government money - health, social security, defence, pensions were all way ahead. And each of those areas - sports, the arts, the lottery - got relatively petty cash from the government.

When you're young, you don't think very far ahead. You just think in terms of the next day, the next week, the next competition. You don't think about injuries that could threaten your long-term health.

I have taught history on the high school and college levels, and am or have been a lecturer at the Smithsonian, The National Institutes of Health, and numerous colleges and universities, mostly on science fiction and technology subjects.