-If you believe that a degree of luck/chance influences the position we occupy in the distribution of income, is it acceptable for the government ro modify this distribution to compensate for bad luck?
Biological and environmental advantages at birth are an important and unfairly distributed explanatory factor in accounting for the ability of individuals to achieve varying levels of merit.
Putting aside this factor for a moment, and assuming individuals are empowered with at least a modicum of autonomy to make free decisions to effect positive changes in their lives, it is my belief that in a modern western economy an able bodied individual wisely investing and working throughout their life, cannot fail to accumulate wealth and succeed. There will be small failures and dips along the way in any one's lifetime, but if you've invested yourself intelligently and for a sustained period, you cannot fail to accumulate ample wealth in the modern Australian economy.
The meritocracy won't be perfectly ordered. The most meritous won't always achieve exactly the most. Corruption and nepotism will always exist. However it will be broadly ordered correctly, and all who are capable, work hard and make sound decisions will profit.
Also, if the government was to redistribute wealth to compensate those affected by bad luck, the taxation imposed to obtain this redistribution will impact on the viability of investments made by those who have to pay for it. It is possible the increased taxation may erode the viability of other businesses in the market, in turn causing a downturn and bad luck for others in the market.
Compensating for bad luck will always have the consequence of serving to subsidize mediocrity.
-Is economic productivity the most efficient/most ethically defensible way to determine the distribution of income?
I can't think of any objection to this distribution.
The appropriate distribution of income can only be fairly determined and set by what employers are prepared to pay and employees will accept in negotiation.
We might even follow Rawls, and argue that the idea of the "free choice" as the fair way to distribute income is problematic - why is it that some people chooise to work hard and act responsibly. Is it (at least partially) because they have grown up in families that promote this work ethic? And if yes, why should people be rewarded for happening to be born into the right families?
This is without doubt the case.
The largest determinant of the person you will become is largely determined by your parents position, particularly with regards to the most powerful of upward motivators, education.
But as zimmerman says, I don't see why a distinction should be made that you're less entitled to that obtained by innate gifts than that supposedly earned by hard work and the application of a dedicated free will. The two are inseparable in origin and effect.
The injustice of biological and environmental advantage at birth is irreconcilable, we can only best help those disadvantaged at birth by providing them with ample freedom to pursue any means towards upward mobility if they choose to so apply themselves, and liberalizing labor laws to facilitate the creation of a diverse range of unskilled jobs to enable them to fit wherever they naturally fall within the social hierarchy. This is compassionate.
They should be rewarded, not because they were born into the right family, but because by rewarding the most capable, it increases economic productivity, which benefits workers from all backgrounds. It may not be perfectly fair that they have obtained their greater wealth through the use of born attributes, but by compensating them when they exercise their born abilities for the increase of economic productivity, a utilitarian benefit is achieved.