Logic alone doesn't tell us much

Sometimes, when you ask a person why they believe something, they'll respond with "logic." This is an evasive response. The only way logic could lead you to a belief is by the rules of inductive and/or deductive inference. But all these rules tell you is the form of the reasoning. They don't tell you anything about the content.

Take modus tollens for example.

If P, then Q
Not Q
Therefore; not P.

By itself, this rule of logic doesn't tell you anything. Or take the transitive property.

P is bigger than Q.
Q is bigger than R.
Therefore, P is bigger than R.

This doesn't tell you anything about whether Jim is taller than Bob. Before logic can tell you anything, you need some premises. You need to have some content in your P's and Q's. Logic alone doesn't tell you much of anything, so when a person says that "logic" is the reason they believe something, they haven't really explained why they believe it. They're just being evasive.

An explanation of why you believe something should be a combination of logic and premises, and when a person asks you why you believe something, they want to know about those premises, not just that you used logic.