Assuming Motive

Hey everyone,

I was wondering if there is a specific logical fallacy related to attributing motive to someone without sufficient evidence. I am thinking especially of the interpretation of literature where a modern reader assumes the motives of an historical figure, even though the author never provides source evidence for that conclusion. For example, someone might say that Churchill pressured the allies to invade Europe through Sicily because he had a personal animus toward Italians, when there is no textual evidence for that statement. I'm thinking there is a logical fallacy going on here but I'm having trouble labeling it. Is this a "False Cause" fallacy? Because it's attributing a cause (Churchill's motive) without sufficient evidence?

That the invasion was where it was is a historical fact, with which all agree. But "why" is speculation unless Churchill stated the reason --- and then we can analyze the stated reasons for their logic. Any attempt to read his mind will be fruitless because we cannot read other people's minds. To determine a motive in law, we look at the objective manifestations (actions) and then infer intent. Far from an exact science. 

As usual, context is important. If say a historian is "suggesting" a motive, this is perfectly reasonable based on the expertise of the historian, as a suggestion or inference is more like an expert opinion rather than a factual claim. It is also more reasonable when the specific person has more expertise to make the specific inference but becomes more unreasonable as the person suggesting the motive has no expertise, but is rather parroting the possible motive and passing it off as their own analysis.

As for a fallacy, if someone were to claim a motive as a fact, without evidence, we would really need to know why they came to the conclusion they did to determine if there is a fallacy, otherwise, they might just be poorly communicating the confidence level.