Is it valid to hear testimony via proxy concerning an absent person?

Primary text

The acceptance of testimony (hearing of evidence) by proxy on behalf of an absent person is valid. This occurs when the agent claims that the absent person appointed him as proxy for a specific matter. This is the position of Al-Shafi'i. The evidence supporting this is that the consent of the absent person is not a prerequisite for hearing the evidence; thus, his physical presence is not required, unlike other matters.