Step 1: Understanding the Concept:
This is a cause-and-effect sentence. The word "Because" signals that the first part of the sentence explains the reason for the second part. The blank must be a word that is synonymous with or directly related to "metaphysics."
Step 2: Detailed Explanation:
The cause is that the writers' seriousness came from their "metaphysics." Metaphysics is the branch of philosophy that deals with the fundamental nature of reality, including concepts like being, knowing, and existence.
Therefore, the writers would be praised for a "bent" (a tendency or inclination) that reflects this focus.
Let's check the options:
\begin{itemize}
\item (A) technical: Relating to practical skills or a particular subject. Not related to metaphysics.
\item (B) discursive: Digressing from subject to subject. Not related.
\item (C) hedonistic: Engaged in the pursuit of pleasure. This is contrary to "high seriousness."
\item (D) philosophical: Relating to the study of the fundamental nature of knowledge, reality, and existence. This is a direct synonym for having a metaphysical bent.
\item (E) scientific: Based on the methods of science. While philosophy and science can intersect, "philosophical" is a much more direct and accurate descriptor for metaphysics.
\end{itemize}
Step 3: Final Answer:
The word "philosophical" is the best choice as it directly corresponds to the writers' use of metaphysics.