Conceptual Framework

Dear sir,
I have yet another doubt regarding conceptual frameworks.

There is a para regarding the measurement issues for elements of financial statements and says

“To use cost should be reliable as, cost is generally known, though cost is not necessary, it is very relevant for the users as it is past orientated. To use a valuation method is generally regarded as relevant to the users as it up to date, but value does have the drawback of not always being reliable. This conflict creates a dilemma that is not satisfactorily resolved as the Framework is indecisive and acknowledges that there are various measurement methods that can be used.

The failure to be prescriptive at this basic level results in many accounting standards sitting on the fence how they wish to measure assets”

Could you explain what this means?
Thanks.