Here’s a lovely paragraph on the role of jazz bass, from Marc Myers in his intro to Part 4 of his lengthy interview with Bill Crow (find at [Invalid or Expired Link Removed] )
Most non-musicians think all jazz bass players are fundamentally alike. They believe they aren't there for us but simply to keep time for the band, the way an unseen transmission is essential for a car. As one person who isn't a bass fan told me some years ago, "There's a reason they stand in the back, behind the piano." To be fair, they are indeed there to keep time for the band, like a human metronome. And in many cases, they do stand in the back or off to the side. But how exactly they keep time—for the band and for us—is where their art thrives. What performing musicians listen for is time as well as swing and edge. In other words, buoyancy. It's hard to explain, but a great bassist will cause the other musicians to levitate, spiritually. The bass is the horse the other musicians ride, depending on the style of music being played. Jazz musicians feel those notes in their spines and when they're solid and strong, those notes give the music lift. And without the bass, music would not be complete, like food without salt or flavor. The bass is essential, and your ear would miss it.
Most non-musicians think all jazz bass players are fundamentally alike. They believe they aren't there for us but simply to keep time for the band, the way an unseen transmission is essential for a car. As one person who isn't a bass fan told me some years ago, "There's a reason they stand in the back, behind the piano." To be fair, they are indeed there to keep time for the band, like a human metronome. And in many cases, they do stand in the back or off to the side. But how exactly they keep time—for the band and for us—is where their art thrives. What performing musicians listen for is time as well as swing and edge. In other words, buoyancy. It's hard to explain, but a great bassist will cause the other musicians to levitate, spiritually. The bass is the horse the other musicians ride, depending on the style of music being played. Jazz musicians feel those notes in their spines and when they're solid and strong, those notes give the music lift. And without the bass, music would not be complete, like food without salt or flavor. The bass is essential, and your ear would miss it.