The Time Traveller's interactions with his dinner guests provide the frame story of Wells's The Time Machine. In other words, they set the stage for a second narrative, the one involving the Time Traveller's adventures.

The Time Traveller's guests represent a cross section of upper-middle-class late-Victorian society. Here we have the pillars of society: doctors, politicians, scientists, and other professional men.

As well as sharing the same social class, the dinner guests—with the notable exception of the narrator—are united in disbelief at the Time Traveller's elaborate story, just as they were united in skepticism when he claimed that he could invent a time machine capable of exploring the fourth dimension.

It's notable that the men of science present at the dinners, such as the Medical Man, Filby, and the Psychologist, are particularly skeptical of the Time Traveller's elaborate claims. As scientists, they require strong evidence to corroborate the Time Traveller's account of his alleged travels.

Given that no such evidence is forthcoming, the Medical Man concludes that the Time Traveller must have hallucinated the whole thing. That's the only possible explanation for such a tall tale.

Other dinner guests subject the Time Traveller to mockery. As a complete ignoramus when it comes to science, the Editor doesn't offer science-based objections to the Time Traveller's account; he simply subjects him to mockery. In the end, though, he's every bit as skeptical as the men of science, it's just that he expresses his skepticism in a completely different, less sophisticated way.