“Take no one’s word for it” is the Royal Society’s motto, and one of the heuristics that should be in everyone’s daily thinking processes.1 The statement advocates the rejection of authority in science and epistemology, and the dominance of reason and persuasion.
The concept of “rejection of authority” has been confounded in recent times with a different idea and movement that do not - usually - relate to the one I advocate here. Revolutionary and anarchic ideas advocate the “rejection of authority” in the sense of overthrowing a government, police or law enforcement force, or a general ruling or upper class in society. This is not the scientific sense of the statement.
“Take no one’s word for it” is the idea that one should not hold a belief or idea
only because an entity that is perceived to be infallible or authoritative decreed it to be so. For example, believing the Earth is flat because the Church decided it was so out of a religious or infallible doctrine and not through the use of reason, evidence, or rationality, is a good example of what “take no one’s word for it” is against.
More relevantly to present times, one should not hold something to be true just because a teacher, professor, or an otherwise academic authority or expert in a field said it was so. One should seek - and demand - explanation and evidence, and give constructive but relentless criticism to an idea offered by anyone before accepting it as ‘true’.
Also, the motto is concerned with rejecting the authority of overwhelming agreement, sometimes referred to as “tyranny of the majority” or “tyranny of the masses.” Once again, the example of the flatness/roundness of the Earth comes to mind. There was general consensus by society - educated and uneducated alike - that the Earth was flat. This led to immediate dismissal, harassment, and ejection of those who begged to differ citing certain arguments and evidence to the contrary. Sometimes the minority is correct in its refutation of what the majority agrees on. In fact, refutation of popular conjectures and criticism and falsification of an idea always arise from a minority. There is no process through which in one instant the majority of experts or researchers in a field discover problems with a theory all at the same instant. A minority or individual must criticize and a majority must be willing to listen and consider the criticism.
As a disclaimer, this is no reason for a dissenting minority to fanatically insist that its dissension is true in the face of the persuasiveness of the currently accepted theory. This would just be another form of authority, that of a minority. The rejection of the authority of majority or consensus is there to allow falsification and improvement to arise, and to encourage the majority to seek criticism for the most accepted of theories and to employ reason and rationality in finding the truth. (This is directly consequential to the current status of scientific publication and peer-review, which suffers from some dangerous flaws. As soon as I write a satisfactory post on the criticisms, I will link to it here.)
Finally, implicit but perhaps not obvious in this general rule is that there is no a priori good reason to exclude anyone from engaging in this process by default. Society often reacts with immediate dismissal if non-established experts question what experts or authority figures state or hold to be common and accepted truth. Those non-established experts could be younger students in a university, non-students and autodidacts, children, or others. When someone from that group asks critical questions or signals disagreement and intent to debate, they are often dismissed by the scientific “ruling class” as inexperienced in the topic and thus unqualified to question it. This dismissal is not based on the non-expert’s argument, but the non-expert’s status. This reactionary dismissal has negative consequences for both parties. Children and other non-experts who wish to learn and engage in discussion will be discouraged if they are judged on silly distracting status labels and not the merit of their question or argument, and on the long run their courage and creativity are stemmed and they engage in self-censorship. On the other hand, the experts grow dull and lazy by only surrounding themselves with those who agree with them or with other experts with whom they can disagree but do nothing about said disagreement in for-the-sake-of-both-our-jobs-and-grants detentes. Ultimately, knowledge creation and human progress suffer.
Conclusion: learn the habit of seeking explanation and response to criticism regarding any truths that are proclaimed self-evident or infallible. Learn to welcome criticism from all interested parties and automatically dismiss none. Do not suppress your own questions and criticisms if they are not sufficiently allayed by individuals or literature because you were told you have no business being skeptical. In your skepticism, rationality, reason, and fallibilism should reign supreme.2