Each moment of training is nothing less than the 'perfected' moment. This is what the genuine Daoist strives to achieve 'here and now'. Obviously, once this has been said (and achieved), a never-ending stream of 'perfected' nowness flows from 'here' to wherever we 'think' we are going - and indeed - wherever we are actually going in the 'material' world (in both space and time, and the nature of the functioning of our minds and bodies). Everything we are 'sensing' is in flux. The question is wherever you can 'see through' this flux using the methodology of Daoist 'neidan' - as it is not just a matter of 'perceiving' and 'making-sense' of this flux - but also a matter of 'penetrating' through the surface level (using a strengthened and focused perception) which 'sees' and 'unites' with that reality (or 'stillness') which lies beyond the 'movement'. What many experience is that this penetration of 'emptiness' is not permanent - as it appears to come and go. This is a common human experience that cannot be escaped. What I can say is that we must also 'penetrate' the confusion (or departure from the 'empty' and the 'still') as it where a continuation of this stable understanding. This is how the notion of 'contradiction' is integrated into that which 'does not depart' from the highest realisation.
The problem emerges when the mind continues to discriminate between 'movement' and 'stillness' - and judges the former inferior to the latter - that suffering re-emerges when the empty-mind seems to 'disappear' - but where could an empty-mind conceivably disappear to? Indeed, the flurrying obscurity of passing thought is not an 'error' even though for a time the traversing of thought across the surface of the mind seems to obscure that which we are a) looking for, and b) attempting to make permanent through 'integration'.
The Chinese Daoist practice of 'neidan', is in reality a transformation of the physical breath into a psycho-spiritual manifestation so that the 'physical' and the 'non-physical' exist simultaneously without paradox or contradiction. This is a normal Chinese cultural trait of the mind which underlies all notions of Chinese cultural construction. As Westerners are taught to separate the 'material' from the 'immaterial' (so that they remain forever separate and distinct), this habitual (cultural) integration can be a stumbling-block, or at least an issue with stepping entirely through the 'gate' of Daoist methodology. Many remain 'this side' of the 'gate' - and become hyper-critical of every other opinion which departs from this interpretation of reality. These are things which we must strive to 'seek-out' and 'uproot' so that the training method is one-hundred percent effective when applied.
There is a cascade of unfolding development that occurs when the entry of the 'gate' is correct and perfected. As individuals, we do not need to be hyper-critical of everything - we merely need to be able to 'see' clearly what is happening, why it is happening and how we can strengthen or weaken the processes as required. We must not construct false experiences whilst waiting for genuine experiences to manifest. After-all, given the right amount of will-power, we can construct virtually any form of 'imaginary' experiences that simply do not exist in the material sense. There is a process of assessment (logical deduction) which is then broken-down into its constituent parts (so as to ensure that this 'logic' repeats itself continuously throughout the entire process of realisation). This is an important observation, as Daoist philosophy within Chinese culture is not considered 'illogical' or 'departing from the ordinary'. This position of logical philosophy should not be confused with the Daoist tendency to 'resist' everyday society, or to 'prefer' nature over that of urban living - as for every retiring Daoist - there is an example of a Daoist Master who lives quite happily within society (such as Master Zhao Ming Wang).
Breath is a material reality (post-natal - later divine sky - later heaven) which is transformed into a psycho-spiritual reality (pre-natal - earlier divine sky - earlier heaven) as the breathing process transitions through the 'neidan' psyche-physical process of training. This is conscious and directed 'returning' to the pure state of life in the womb before the human-mind was broken into 'subject-object' perception by the birth-process into the gross physical world, and the human breath and mind 'separated' into two distinct and seemingly 'different' physical aspects of conscious life. The practice of 'nei-dan' is a methodology that 'reverses' or 'returns' the post-natal state of diverse mind-body existence back to the pristine state of the fully integrated 'oneness' of pure pre-natal state. Any mind-set, physical habit or reaction which diverts the practitioner away from this position has to be carefully removed from the system.
With Metta
Adrian