 When struck, an object vibrates in an odd but characteristic fashion for a brief time before it settles into vibrating at its natural frequencies, if it has any. Like natural frequencies, these attack patterns are relatively stable dispositions of objects to vibrate when thwacked. Similarly, objects’ vibrations decay characteristically. Attacks and decays are stable dispositions of objects to vibrate when thwacked, just as natural frequencies of vibration are. (Kulvicki 2008: 14)