The author uses ethos, or the appeal to authority, to establish the credibility and authority of the Time Traveller as a narrator and a scientist. Throughout the story, the Time Traveller is portrayed as a man of science and reason who is driven by a desire to understand the world around him. He is described as having a deep understanding of the scientific concepts behind time travel, and he uses this knowledge to explain his experiences to the other characters and to readers. This establishes him as a credible and authoritative narrator—one who is able to provide a scientific and rational explanation of the world he encounters.
Wells also draws on the authority of science itself to fortify the concept of time travel:
'Scientific people,’ proceeded the Time Traveller, after the pause required for the proper assimilation of this, ‘know very well that Time is only a kind of Space.'
Here, Wells uses the concept of "scientific people," or people to whom science is legible, to make his theory compelling. The reader is prompted to consider the protagonists' proposition, and suspends disbelief long enough to accept the premise of Wells's science fiction narrative.
The concept of time travel is described in a detailed and objective manner, which further establishes the protagonist as a reliable narrator. The Time Traveller's observations and descriptions of the world he encounters are not colored by his personal biases or emotions, but rather are grounded in his scientific curiosity and desire to understand the world around him.
Finally, the Time Traveller also references other members of the scientific community, contributing to a sense of his scientific authority: “Professor Simon Newcomb was expounding this to the New York Mathematical Society only a month or so ago.” This allusion to a broader scientific community that stands in agreement with his thinking lends credence to his claims and situates his narrative within the broader project of scientific discovery.