They are NOT encouraged to form their conscience on the Precepts of The Church!
So very many fall for this gross, evil deception. Their false reasoning affects whatever faith they might have had! Once they have succumbed to this reasoning - even if it is false reasoning, it is still reasoning - it is so very easy to base other decisions concerning matters of faith on this basis. Thus, day by day, they wander further from The Faith.
It is like verging off the northern route, going nor'-nor'-west. At first, it seems virtually the same direction but the further along the route one travels, the further away from the desired destination one goes.
Clearly, there is a difference here, in faith and reason.
Talking to a Protestant makes this very clear for his reason tells him that he is smart in going straight to Jesus, while we Catholics, strange creatures, waste our time becoming acquainted with Mary, giving her honour that could have gone to Jesus Christ!
This reasoning, sensible as it may at first appear, leads him away from the true, full Christian Faith that is only found in Catholicism!
But while faith can not be detached from faithful and true reasoning, it is more then reasoning -  it is more then knowledge.
It is even a thing apart from Truth - or perhaps a companion to Truth? And I write this last sentence with some trepidation for I am one who holds Truth in adoration, for Truth is God; Truth is Christ The Lord.
This I believe. This is part of my faith.
I only say that because I, even though I be a child of Mary and a child of The Eternal Father, am so extraordinarily limited in my intellectual and reasoning power.
We are told the Truth that in the one God there are three really distinct Persons equal in all things, having only one and the same divine Nature, (Penny Catechism 18) and we clearly perceive that this is something great and that it explains how The Eternal-son became Man and still prayed to His Father in Heaven. We clearly perceive that Jesus can speak of sending The Holy Spirit upon mankind.
We can then understand why we are baptised in the Name of The Father, The Son and The Holy Spirit.
But in fact, while these seem reasonable, sensible and even common-sensical, we do not comprehend AT ALL, the complete Truth of One God and Three Persons.
We do not even BEGIN to grasp the fullness of this astonishing Truth. Not only that, but even in Heaven we will not grasp this fullness of the absolute Truth. When it comes to the final analysis,  this is only possible to God Himself.
Thus I began to perceive the wondrous nature of faith, as apart from reasoning but as a divine companion to reason.
Thus do we perceive the Mystery of The Holy Trinity, and we somehow know this to be Truth even though we only glimpse the Fullness of this - and so, we arrive at faith - or faith arrives at us.
This 'somehow know' is what faith really is. And the 'somehow' is a work of God in us.
However, and I say however with some concern, because even though I be Catholic and even though I have the great Gift of Faith, I remain a pathetic creature, prey to every temptation and subservient to an inadequate intellect and false reasoning.
And yet once more - again - and not for the last time - my faith tells me in powerful terms you can not rely on your own reasoning. If you follow your conscience, created in your own inadequate likeness, you will fall in a rotting heap - even finish in hell! My faith tells me, as a simple follow-up to that simple fact, that
you can ONLY rely on your holy Mother, The Church.
I say who or what else?
This is SO simple to me, but I have come to realise that this is only a gift of faith.
It boils down to some simple things:
my own capacity to know Truth is so inadequate
as to be pathetic;
I can not turn to another individual
to discover Truth
for he is just as inadequate as I am;