It is tricky business to determine who or what an authority might be. Some of the group felt that God is the ultimate authority while others expressed doubt that this could be the case since, in their opinion, no such entity as God exists. The former have scripture on which to rely as authoritative, but even some believers acknowledged that, having been written by men, not all scripture could be relied on as infallible.
While we avoided debating the question of whether God does or does not exist, those not relying on scriptures were left the difficulty of establishing valid criteria for a reliable authority. Perhaps we can look to those who have education, knowledge and experience in a particular area as an authority in that field, but this too is an imperfect yardstick. Our understanding of science changes over time, so even qualified scientists may be questionable as authorities. In fact, if scientists were not questioned, no progress would be made. It is only by doubting and questioning that new discoveries come about.
One might be well advised to look with caution on those who proclaim themselves to be an expert or an authority. From ancient history to the present time, there are those who seek to be considered as an authority for prestige, monetary gain, the ability to manipulate those less knowledgeable or to try to establish a questionable thesis. The true authority or expert is recognized as such not by him/herself but by their peers and established accrediting bodies.
So what is left for us to base our decisions on if we cannot totally rely on authorities? Perhaps the best that can be done is to take the time, trouble and energy to think for ourselves. Weighing and balancing conflicting claims, avoiding becoming victims of our own preconceived notions and respectfully questioning the credentials of those we choose to consider as authoritative, will, more often than not, enable us to make the best decision possible.