Alcohol comes from the Arabic "al-kuhl" which was the name of a body-eating spirit. In fact, the English "ghoul" comes from the same word.
When Arab alchemists' ingested alcohol their senses deadened and they named the substance according to its "body-taking" qualities. Knowing this, European speakers who understood its etymology coined the use of the term "spirits" for alcohol.
The use of the term spirits for alcohol goes very far back so it's impossible to know for sure due the lack of written evidence, but this is the simplest answer to the question, and, in my opinion, the most likely to be true.
When Arab alchemists' ingested alcohol their senses deadened and they named the substance according to its "body-taking" qualities. Knowing this, European speakers who understood its etymology coined the use of the term "spirits" for alcohol.
The use of the term spirits for alcohol goes very far back so it's impossible to know for sure due the lack of written evidence, but this is the simplest answer to the question, and, in my opinion, the most likely to be true.