RBA board faces a number of dilemmas today

At the same time, depreciation of the US dollar would strengthen US exports, especially if the US used a less consumerist approach to economic strategy.

But the US budget has deficits "as far as the eye can see" and US cash-interest rates are close to zero, hardly a scenario to encourage hard work and high saving.

China has been attempting to slow its runaway growth while the US has been showing signs of a double-dip recession.

Along with fears of a euro-zone debt crisis, the net result has been fears of a renewed global slowdown and this has increased uncertainty (raising market volatility) and produced renewed net falls in global share prices.

How these complex currents and cross currents play out provides the second major dilemma facing the RBA board today.

Domestically the uncertainties are real, too.

Like the global economy, Australia has a two-speed economy and as deputy-governor Ric Battellino has said, two speed for Australia usually means "fast" and "very fast".

The second leg of the present great resource boom is clearly under way, but if the world has another down-dip there will be some check to the optimism of miners and the many contractors working in the mining industry.

And there is a home-grown reason for the mining boom to slow: the "great big new mining tax".

The more hysterical commentators have spoken of a "capital strike" by the mining industry and it seems clear a good number of projects are on hold until this unexpected obstacle is dealt with.

Retail sales are said to be weak and there are many good discounts about.

Other things equal, this is a good thing, but if exports begin to slow and business investment is revised down, the gloss will come off Australia's so far excellent post-crash economic performance.