Possibility and Practicality

Possibility and Practicality - What is the barrier between where we currently find ourselves and that which we dare to dream as possible. Is it only one thing or a number of contributing factors. What are the limits of what is possible, is possibility limited by the practicality of the desired event. If something is possible but impractical, is it only the method of the approach which needs adjustments to allow the realisation of an idea.