So goes the popular and wise saying. It was also the subject matter of an article recently provided to the writer in Canberra by a colleague, entitled The Law of Unintended Consequences: Shakespeare, Cobra Breeding and a Tower in Pisa.

It made for fascinating reading and was provided to support my decision to abstain on the Senate Bill dealing with the abolition of mandating COVID vaccination.

Readers will know the writer's view in support of COVID vaccination and his equally strong stance against making it mandatory.

A vote for the Bill would've been a vote for this: "The Commonwealth must not fund a state... if a state is reasonably likely to discriminate against a person on the basis of whether the person has received a COVID-19 vaccination." S7(2)(b).

The writer supported the principle of opposing mandating vaccination in the Bill, not so much the mechanism of enforcement which meant stopping all federal funding to Tasmania.

This would, in fact, have been an intended consequence.

As John Muir said, "When we try to pick out anything by itself, we find it hitched to everything else in the universe".

Seeing the whole picture is vital. Mere perception, whilst deemed to be everything in politics by some, is never good enough.

Think of the introduction of rabbits and foxes for sport by our forebears. Good for sport - not so good for environment or farming.

Or the cane toad. Good to get rid of a particular pest, but in turn, it became an even worse, noxious pest itself.

That's why in developing public policy we need what is called 'second thinking' or discernment.

The consequences of proposed public policy schemes means we always need mature, considered thinking.

Because for every scheme there will be a scam developed by those with fertile minds which lack a moral compass - think Pink Batts, school halls or the baby bonus.

All good ideas in themselves, but with consequences unintended, albeit some of us might say were foreseeable.

But a classic from the British Empire days is when a reward/bounty was offered for people who killed and turned in cobras. Reacting to the incentive, the enterprising turned to breeding cobras.

So in response to the scam, the scheme was scrapped, so the scammers released the excess cobras which saw even more cobras than before the scheme was introduced.

Vietnam tried a similar scheme for rats with identical consequences.

All of which made the writer lament the lack of entrepreneurial spirit in our colonial forbears in response to the bounty paid for the Tasmania tiger. An opportunity gone begging.

The leaning Tower of Pisa ships in huge numbers of sightseers to its town. Its purpose was never as a tourist attraction. An engineering design fault saw its foundations fail.

Today they are underpinned and the tower is stabilised.

An engineering failure is turned into a tourism gold mine hundreds of years later. Who would have thought it?

At least this unintended consequence was beneficial, although one doubts predictable.

And for those wondering how Shakespeare got a mention, get an eyeful of this ... would Shakespeare, while scribbling away all those years ago, think his writings in England would be responsible for the introduction of starlings into the US? How so?

Well, a lover of all things Shakespeare - especially the play Henry VI - saw a fellow who rejoiced in the name Schieffelin decide he wanted the same experience as Shakespeare when it came to birds which could be seen out of his window. So he released 100 starlings (non-native to the US) over two years.

Today those 100 starlings are the breed stock of 45 to 100 million estimated starling population in the US today. And all because Shakespeare wrote Henry VI in about 1590.

Three hundred years later, Schieffelin releases 100 starlings and 130 years after that, starlings are a pest in the US.

No one could have or would have predicted such an outcome.

While no sane person would hold Shakespeare responsible for the US' starling plague it reminds us that there are unintended consequences to every decision we make and action we take.

If we don't anticipate unintended consequences, we can't expect to achieve our desired outcomes.

For those in politics, policy development and legislation, we need to look beyond the superficial and the immediate and treasure substance, analysis and discernment. Not necessarily popular in the short term but it makes for the better outcome.