The fundamental physical point
1 The start point for physics is that there is: a) physical existence independent of sensory detection (eg sight, hearing, etc), and b) alteration thereto. This is proven by the fact that sentient organisms receive physically existent phenomena (eg light, noise, etc, which are themselves the result of an interaction between other physically existent phenomena), and that when these inputs are subsequently processed and can be compared, difference is identified.
2 Whatever comprises physical existence, which may involve more than one type, and something not yet known, it must have physicality. That is, whether it be that which is deemed to exist, or that which is deemed to cause alteration thereto, there must always be corresponding physically existent phenomena. Nothing (entity or process) can be deemed to be physical, or have a physical effect, unless that is so.
3 Any given physically existent phenomenon cannot be in more than one physically existent state at a time, otherwise, by definition, it is not a physically existent phenomenon, it is more than one. Therefore, what is physically existent (a reality) is that state which is physically existent as at any given point in time (as in timing). A point (unit) in time being the fastest rate of change in the entirety of reality, because timing is the rating of change. And the requirement is to determine that physically existent state, in any given sequence, where no form of change is occurring, ie to differentiate one from another.
4 So reality is a sequence. There is no state which is commonly referred to as the future, because that does not exist. Hence any concept which involves the notion of change to it, or that it can have some physical impact, is incorrect, because there is nothing in existence to affect, or be able to have an effect. Neither does what is known as the past exist. Representations of it, from the perspective of the sensory systems, can exist as physically existent phenomena (eg light), but these too have a sequence. It is just that one of their features is that their physical state, from the perspective of the sensory systems, remains unchanged (or nearly so). All that exists is that which can be differentiated at any given point in time, which is commonly known as the present.
5 Notions such as oscillation, reaction, etc, are ontologically incorrect. Even at a higher level of conceptualisation, reality is in no sense occurring 'backwards'. This just involves the apparent repetition of a previously existent state, though in terms of physicality, it is probably impossible for an identical entire configuration of any given state to re-occur. For example, leaving aside the actual elementary constitution, a sequence could be represented as ABCCDBEFGGGAB....What is happening is that, at the level of differentiation being applied, A & B are re-occurring as the sequence progresses, and C & G do not change in that duration differential, G taking longer than C to do so.
6 The sequence of reality, whether considered as an entirety, or as any given physically existent component thereof, can only occur in 'one direction' because only what is known as the present is in existence. Furthermore, by definition, the actual physical state of any given present, must be a function of the previous one, because influence cannot 'jump' physical circumstance, neither can a non-existent state have influence.
7 Similarly, the explanation as to how and why that different state occurred, must ultimately be a function of the lowest level of that which constitutes the previous state. In any given circumstance, cause must ultimately be traceable to, and be a function of, the fundamental components of the circumstance which caused it. Also, any given physically existent state, must be definite, otherwise it could not occur. To physically exist inherently involves definiteness, and discreteness. Continuousness involves no change whatsoever to any given physically existent state.
8 It is probably always going to be impossible for humans to identify the precise physical constitution of a discrete physically existent state, especially if it involves any degree of complexity. Similarly with respect to differentiating the precise physical interrelationship of cause in any given circumstance which involves some degree of complexity. However, this is a 'failure' in human capability, and the issue should not be attributed to innate characteristics in reality.