Stability

A system is stable with respect to certain of its variables if these variables tend to remain within defined limits. Such a system may be stable in some respects and unstable in others. An adaptive system maintains stability for all those variables which must, for favourable operation, remain within limits. An important feature of system stability is that it is a property of the whole system and cannot be assigned to any part of it; it belongs only to the combination of parts and cannot be related to the parts considered separately. The presence of stability always implies some coordination of the actions between parts.