Often when we think of an “authoritative style,” we think of someone who speaks impersonally and with confidence, describing how some aspect of reality works without involving their own or the reader with “I,” “you” or “we.” This approach to earning the reader’s trust is all about setting aside the personal to pursue objective, neutral, unbiased pronouncements. It requires the writer to step back from their own personality and feelings to ally their speech with impersonal truth.
A formal style indicates that the writer takes seriously the institution they are speaking for and the rigorous expectations of argument. Traditionally, academic writing is expected to be relatively formal and distanced.
Think of a judge in black robes presiding over a courtroom. The judge is there as an official, not a private individual, and what they say is understood to represent the rule of law, not their personal opinion. When they speak, they use formal language and usually describe events impersonally. As a representative of the law, they represent the government and the interests of the people as a whole.
Think also of a professor asked to speak on a news program about their area of expertise. Despite a climate scientist’s degrees and institutional affiliation, we may not trust their personal musings about the future of humanity while flying over melting Greenland ice. Their impersonal style of speech and their focus on facts about climate, reassure us that what they tell us is unbiased, objective, neutral, and vested with all the authority of academic rigor. If they use “we” it will be to refer to their academic colleagues, as in “As climate scientists, we look at overall trends rather than specific snowstorms or heat waves.” We will expect the scientist to speak in definite, precise language and to speak with a certain dignity and seriousness.
Formality and distance have their disadvantages as well as their advantages. They can make the argument seem objective and solid, but they can also alienate the reader. After all, distance means we are being pushed away. Our trust in a formal argument depends on our trust in the institutions it represents, like the government or academia. The reader may be disillusioned with these institutions or may never have trusted them in the first place. The reader may not believe that the topic calls for neutrality. We may wonder, too, what personal opinions and experiences and feelings the writer is hiding behind a mask of neutrality.