Primacy of consciousness refers to a mistaken belief that comes from a misinterpretation of quantum physiques. The central concept is that consciousness is the main 'fabric' of reality, and that the physical reality around us results from that. This is of course an empowering concept and one that finds its way into much self-help literature as well as many books on psychology and health. However it is also one that takes liberties and draws unscientific conclusions from the evidence.
Collapse of the Waveform
Without getting bogged down in quantum physics here, the theory is the result of the 'collapse of the waveform' that has been noted by quantum physicists. Essentially studies have demonstrated that it isn't possible to state the exact position or the exact momentum of a particle until it has been measured. All particles behave like waves and like solids meaning that they aren't technically in any one place at any given time but rather have a probability of being found anywhere in relation to that wave. Saying where the wave-particle is precisely then is much like saying where a ripple in a pond is – it's spread out and everywhere and constantly moving.
However the amazing part happens when we measure the precise location of that particle – which can be achieved by tagging it for instance using a special filter to only detect particles with certain filters is one way to do this (look up the 'double slit experiment' for a more in depth demonstration) – it suddenly 'snaps' into place and now has a finite position and amount of energy.
In other words it's the act of measuring the particle that gives it its definite properties and up until that point it exists in a kind of flux. It's not that we can't predict its precise position – it's that up until this point it has had no precise position.
Of course this is something that is a little upsetting to psychologists, and it's something that doesn't seem very scientific by nature, and this is why every exponent of mysticism and everything else has jumped on the bandwagon and tried to give credit to their claims by just saying 'it's quantum'. And likewise many self-help books have jumped to the conclusion that this data means that consciousness is the only 'real' thing and that we create the physical world through our existence. This humanity-centric view is one that seems appealing, but unfortunately this is rather a big jump.
First of all, this is only one explanation of the 'collapse of the waveform' (as it is known). Another is the 'many worlds' theory which has been popularized in science fiction and explains the universe as branching off into different realities at every point. We are living in one possible version of that reality and that's why the wave particles collapse into just one position out of endless possibilities. This of course has rather large implications of its own, and it's something that is rather controversial as well – but it is still just a demonstration that there's more than one explanation here. Most scientists are patiently waiting for an explanation that makes sense and that bridges the gap between classical, macroscopic Newtonian physics and the world of quantum uncertainty and waveform collapse.
Likewise assuming that our consciousness controls reality doesn't really have much foundation in science even if that's your chosen explanation. It doesn't explain how our consciousness selects one of the probabilities for instance, nor what happens when a particle has multiple conscious observers, or what happens when someone consciously views our brain. Nor does it explain how brain damage can cause alterations in our consciousness. Most fundamentally though, it fails to acknowledge that it is not the act of observation that causes the collapse, but rather the act of measurement – which are two different things and can exist exclusively of each other.
Yes there are a lot of unanswered questions, and yes there may well be a lot more to the nature of the universe – but it's very much too soon to start claiming we have the power to control reality with our will. Let's not get ahead of ourselves...