The central problems for a philosophy of change are the relationship of change to time, and the relationship of both of them to us. Although change is a fundamental element of the perceived world, a permanent theme in both Eastern and Western philosophies is an other-worldliness according to which the restless everyday world of changing things and events must be regarded as unreal in comparison with a more fundamental immutable reality. The first expression of this in the western tradition occurs in Parmenides. The arguments of Zeno of Elea against motion are usually interpreted as partly a defence of Parmenidean monism. The backlash came with Heraclitus, whose vision of the world as eternally in flux nevertheless found something contradictory in the notion: ‘we step and we do not step into the same river, we are and we are not.’ The idea that there is a contradiction in the notion of change is defended in modern times by McTaggart (see a-series), who also thought that reality had to be conceived of as essentially static, with apparent change an artefact of a mental perspective. The idea that the changing, decaying world is a reflection of an eternal, incorruptible, and changeless world is central to Christian metaphysics, and finds expression in Kant’s doctrine that time is merely the form of inner sense, imposed by the mind. In absolute idealism, notably that of Bradley, there is the same doctrine that change is contradictory and consequently unreal: the Absolute is changeless. A way of sympathizing a little with this idea is to reflect that any scientific explanation of change will proceed by finding an unchanging law operating, or an unchanging quantity conserved in the change, so that explanation of change always proceeds by finding that which is unchanged. The metaphysical problem of change is to shake off the idea that each moment is created afresh, ex nihilo, and to obtain a conception of events or processes as having a genuinely historical reality, really extended and unfolding in time, as opposed to being composites of discrete temporal atoms. A step towards this end may be to see time itself not as an infinite container within which discrete events are located, but as a kind of logical construction from the flux of events. This relational view of time was advocated by Leibniz and a subject of the debate between him and Newton’s absolutist pupil, Clarke.