64.7 Now a rhythm is recognisable and is so far an object. But it is more than an object; for it is an object formed of other objects interwoven upon the background of essential change. A rhythm involves a pattern and to that extent is always self-identical. But no rhythm can be a mere pattern; for the rhythmic quality depends equally upon the differences involved in each exhibition of the pattern. The essence of rhythm is the fusion of sameness and novelty; so that the whole never loses the essential unity of the pattern, while the parts exhibit the contrast arising from the novelty of their detail. A mere recurrence kills rhythm as surely as does a mere confusion of differences. A crystal lacks rhythm from excess of pattern, while a fog is unrhythmic in that it exhibits a patternless confusion of detail. Again there are gradations of rhythm. The more perfect rhythm is built upon component rhythms. A subordinate part with crystalline excess of pattern or with foggy confusion weakens the rhythm. Thus every great rhythm presupposes lesser rhythms without which it could not be. No rhythm can be founded upon mere confusion or mere sameness. 64.8 An event, considered as gaining its unity from the continuity of extension and its unique novelty from its inherent character of 'passage,' contributes one factor to life; and the pattern exhibited within the event, which as self-identical should be a rigid recurrence, contributes the other factor to life. A rhythm is too concrete to be truly an object. It refuses to be disengaged from the event in the form of a true object which would be mere pattern. What the pattern does do is to impress its atomic character on a certain whole event which, as one whole bearing its atomic pattern, is a unique type of natural element, neither a mere event nor a mere object as object is here defined. This atomic character does not imply a discontinuous existence for a rhythm; thus a wave-length as marked out in various positions along a train of waves exhibits the whole rhythm of the train at each position of its continuous travel. 64.9 The very fact of a non-uniform object involves some rhythm. Such objects appear to our apprehension in events at certain stages of extensive size, provided that we confine attention to those organisms with stability of existence, each in close association with one physical object or with one set of causal material objects. Molecules are non-uniform objects and as such exhibit a rhythm; although, as known to us, it is a rhythm of excessive simplicity. Living bodies exhibit rhythm of the greatest subtlety within our apprehension. Solar systems and star clusters exhibit rhythm of a simplicity analogous to that of molecules. It is impossible not to suspect that the gain in apparent complexity at the stage of our own rhythm-bearing events is due rather to our angle of vision than to any inherent fact of nature.