The sentence compares two different levels of negative reaction from scientists:
1. A relatively mild reaction toward unusual findings (those that "fail to mesh").
2. A much stronger reaction (contempt) toward foundational theories that threaten their work.

Blank (i): Initial Reaction
- Context: If a finding does not "mesh" with a scientist's research, they are likely to show skepticism.
- Fit: B. doubt describes the appropriate, cautious level of initial skepticism before evidence is fully examined.

Blank (ii): Comparison
- Context: The first reaction (doubt) is being measured against the second, much stronger reaction (contempt). The keyword "nonetheless" sets up this contrast, implying that the initial doubt is much weaker.
- Fit: E. positively muted means the response is very restrained or minimal when compared to the next, much harsher reaction. This clearly establishes the necessary difference in severity.

Blank (iii): Escalated Reaction
- Context: The blank describes an attitude that is stronger than the first response and is placed before the phrase "if not downright contemptuous." Therefore, the word must be a strong negative attitude that is slightly less extreme than contempt.
- Fit: I. dismissive means regarding something as unworthy of serious consideration. This is a very strong, negative reaction that perfectly fits as the step just below "contemptuous," especially when confronting a theory that questions the "very foundation" of their work.