Starting from the space representation of the field coordinate, a causal interpretation of the Schrödinger picture of relativistic quantum theory has been constructed. The Schrödinger picture for a neutral, spin 0, massless field Ψ Ψ [ ψ ψ ( x , t ) ] = R [ ψ ψ ( x , t ) ] e S [ ψ ψ ( x , t ) ] , with R [ ψ ψ ( x , t ) ] , S [ ψ ψ ( x , t ) ] real-valued functionals, can be shown to lead to