In economics, one of the most important concepts is 'opportunity cost' - the idea that once you spend your money on something, you can't spend it again on something else.
Climate change is a global problem. The planet is warming because of the growing level of greenhouse gas emissions from human activity. If this trend continues, truly catastrophic consequences are likely to ensue from rising sea levels, to reduced water availability, to more heat waves and fires.
It's not a 24-hour news cycle, it's a 60-second news cycle now, it's instantaneous. It has never been easier to get away with telling lies. It has never been easier to get away with the glib one liner.
It is our job above all in politics to tackle the big issues and to explain them, and have the honesty to say to people, 'There are no easy solutions here.'
Are not the gays who seek the right to marry, to formalise their commitment to each other, holding up a mirror to heterosexuals who are marrying less frequently and divorcing more often?
We are already experiencing the symptoms of climate change, especially with a hotter and drier climate in southern Australia - the rush to construct desalination plants is an expensive testament to that.
I do not believe we can effectively move Australia to a lower emission economy, which is what we need to do if we're going to make a contribution to a global reduction in greenhouse gases, without putting a price on carbon.
Mitt Romney speaking to a $50,000-a-plate Republican fundraiser says he doesn't have to worry about the 47 per cent of Americans who don't pay tax. He was not counting on the smart phone recording his speech and then posting it on YouTube.
If Margaret Thatcher took climate change seriously and believed that we should take action to reduce global greenhouse emissions, then taking action and supporting and accepting the science can hardly be the mark of incipient Bolshevism.
China and India will take the global leadership on climate change: they are suffering for it.
If consulted by friends about marital dramas, I always encourage the singles to marry, the married to stick together, the neglectful and wayward to renew their loving commitment and the wronged to forgive.
I will go to the next election saying to Australians, vote for me, vote for the Liberal Party, and I will become your PM. So I'm offering myself as the alternative PM - that's one way people describe the Leader of the Opposition - but I'm not in politics for myself to realize a personal ambition.
Broadcasters or politicians or writers who think that they are respecting Struggle Street, the battlers, by dumbing things down into one-line sound bites are not respecting them, they are treating them with contempt. It's our job above all in politics to tackle the big issues and to explain them.
Let us be honest with each other. The threat to marriage is not the gays. It is a lack of loving commitment - whether it is found in the form of neglect, indifference, cruelty or adultery, to name just a few manifestations of the loveless desert in which too many marriages come to grief.
I am an ambitious person, but I am not ambitious in the sense that I want jobs only for the sake of them... I am here to do things I think are worthwhile. I am always careful that the political positions I take are consistent with good policy. I would not want to be prime minister of Australia at any price.
The most effective check and balance on government has been an independent press which maintains its credibility by ensuring that its criticism is balanced and based on fact - based indeed on solid journalistic work.
Anyone who thinks it's smart to cut immigration is sentencing Australia to poverty.
Study after study has demonstrated that people are better off financially, healthier, happier if they are married, and indeed, I repeat, if they are formally married as opposed to simply living together.
Governments enjoying surpluses have a very strong temptation to splash money around, and while tax cuts are always appealing, cutting taxes at the top of a boom runs the real risk of creating a structural deficit when the boom subsides.
It's really corny to say, but if you are happily married and have good kids, that is about 98 per cent of what you should be seeking to achieve.
