Source: Jack E. Henningfield, PhD for the National Institute on Drug Abuse (NIDA
“If you can pass a field sobriety test, shouldn’t you be OK to drive?”
Yes.
But we are not just talking about driving.
We are talking about behaving in a world full of other people.
While you take care of the kids. While you work at the bank. While you go shopping. While you hunt. While you teach. While you check in on your parents. While you go to school. Etc.
To deliberately impair yourself is immoral. You are making yourself stupider, with lesser inhibitions, less rationality, and poorer judgement. I say that is immoral. You make us all more vulnerable to your deliberately stupidified self, and some are extremely vulnerable to you, for example, your kids and your spouse and your neighbors.