A song by a goth band called the Sisters of Mercy, taken from the First & Last & Always album.
The title refers to that state where one's logic discounts all possible personal efforts, usually because under the influence of amphetamine, nothing is too much to be bothered with.
In other words, by Amphetamine Logic, I might decide to walk home from Slimelight - a night-club in London to my parents' place in the West Country not considering the walk excessive.
On the other hand, other people also become unimportant as one is completely detached and self-centred.
On American pressings of First & Last & Always, the title of the song curiously leaves out the word "amphetamine," and the word is dubbed out of the vocals.
Give me one good reason. Give me my amphetamine logic