In my view, the necessary objective is to accept market risk when the likely return / risk profile is attractive, based on
observable measures of valuation and market action, and to avoid, hedge, or diversify away those risks that don't carry attractive return / risk profiles on average.
The
measures of valuation and market action that define each «Market Climate» are factors that can be tested in decades
of historical data, are objective,
observable, and have strongly affected the average profile
of return and risk in the markets over time.