In discussion it is not so much weight of authority as force of argument that should be demanded. Indeed the authority of those who profess to teach is often a positive hindrance to those who wish to learn; they cease to employ their own judgment, and take what they perceive to be the verdict of their chosen master as settling the question.

[Non enim tam auctoritatis in disputando quam rationis momenta quaerenda sunt. Quin etiam obest plerumque iis qui discere volunt auctoritas eorum qui se docere profitentur; desinunt enim suum iudicium adhibere, id habent ratum quod ab eo quem probant iudicatum vident.]

Marcus Tullius Cicero (106-43 BC) Roman orator, statesman, philosopher

De Natura Deorum [On the Nature of the Gods], Book 1, ch. 5 / sec. 10 (1.10) (45 BC) [tr. Rackham (1933)]
    (Source)

(Source (Latin)). Alternate translation:

For the force of reason in disputation is to be sought after rather than authority, since the authority of the teacher is often a disadvantage to those who are willing to learn; as they refuse to use their own judgment, and rely implicitly on him whom they make choice of for a preceptor.
[tr. Yonge (1877)]

In discussion it is not so much authorities as determining reasons that should be looked for. In fact the authority of those who stand forward as teachers is generally an obstacle in the way of those who wish to learn, for the latter cease to apply their own judgment, and take for granted the conclusions which they find arrived at by the teacher whom they approve.
[tr. Brooks (1896)]

For when we engage in argument we must look to the weight of reason rather than authority. Indeed, students who are keen to learn often find the authority of those who claim to be teachers to be an obstacle, for they cease to apply their own judgement and regard as definitive the solution offered by the mentor of whom they approve.
[tr. Walsh (2008)]