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The dynamics of the dunefoot along a 160 km portion of the Dutch coast has been investigated based on a data set of annual surveys dating back to as early as 1850. The linearly detrended (or residual) dunefoot positions comprise an alongshore uniform and an alongshore non-uniform component. The former is expressed as 10 to 15 m of landward retreat along extensive (>10 km) stretches of coast during years with severe storm surges and as up to 5 m of seaward advance during years without significant storm activity. The latter, alongshore non-uniform component is organized in sandwave-like patterns, which may have a longevity of decades to up to the duration of the entire data set (150 years). Their wavelengths vary along the coast, from 3Ð5 to 10 km; migration rates are 0-200 m a 1 . Dunefoot sandwaves are shown to be the shoreward extensions of similar sandwave patterns in the beach position. The non-uniform dunefoot behaviour constitutes at least 80 per cent of the total residual dunefoot dynamics, implying that along the Dutch coast residual dunefoot variability is controlled by temporal and spatial variability in beach characteristics, and not by storminduced uniform erosion. Various potential mechanisms causing beach sandwaves are discussed.

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A distinction must be made between various levels of thought. For a definition of life the formulation on the level of natural sciences, i.e. the biological definition, will not be the same as the philosophical expression. The biological definition is based on the phenomenon of life, the appearance, and considers the molecular structure and functions of a cell. The philosophical definition regards the being and it is proposed to consider life as transcendental. It is argued that there is no opposition between these definitions, but that together they can deepen our insight into the problems of matter and life.

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