So James Levine has a medical condition that weakens him. “Before Met fans or administrators panic, some perspective is called for. Although conducting requires mental and physical stamina, the job is hardly limited to those who fit the standard image of the kinetic and charismatic wizard of the podium, like the young Finnish firebrand Esa-Pekka Salonen of the Los Angeles Philharmonic. Some of the greatest conducting of the last 100 years was done by aging and physically enfeebled maestros who still inspired orchestras through their insights and uncanny abilities to convey intention with economical hand gestures, facial expressions and sheer presence.”