Atheistic morality (cartoon)
A cartoon rendition of the so-called “killing spree paradox”, often put to atheists, by believers, who raise the question about the basis of atheistic morality.
In atheism, killing spree paradox is the generalized question, oft-posed by theists semi-curious about atheism, that if there is no god what stops a person from going on a killing spree.

Chemical morality
When one begins to grapple with the question of morality in a godless universe, and or the premise of a human conceptualized as a molecule (or chemical), governed by physicochemical principles, commonly one of the first queries to come to mind, for many, concerns the seeming universe without morals issue, typified by the query: “what’s stopping me from going on a killing spree”, or something along these lines, if there is no God and or the universe is moral-less.

Crebillon … treats the passions like playing cards, that one can shuffle, play, reshuffle, and play again, without their changing at all. There is no trace of the delicate, chemical affinity, through which they attract and repel each other, reunite, neutralize [each other], separate again and recover.”
Johann Goethe (1799), “Letter to Friedrich Schiller”, Oct 23

The following are other related quotes:

“The morality Libb would propose, is never explicitly proposed. Rather, Libb, each time after he says ‘life does not exist’, goes on to claim that this should have something to do with morality. To me the most obvious moral principle that would follow from ‘life does not exist’ is that ‘it really doesn’t matter whether we would kill somebody’, since life does not exist. Clearly, such reasoning is highly immoral and I hope that Libb does not propose this?” (pg. 97) .... Can Libb be a serial killer if it doesn’t really matter since: one, life does not exist, so you cannot remove it, and two if the negativeness of dG tells me that killing many people is OK, then I must do so.” (pg. 104)
David Bossens (2013), Debates of the Hmolpedians [2]

“What’s stopping me, if I am just a molecule, and morality or the judgment of god does not exist, from going on a killing spree?”
— Rodolfo Flores (2013), In Person Query to Libb Thims, Oct 10; compare: molecules in motion

(add discussion)

Dostoyevsky
See: Dostoyevsky dilemma
The original statement of the premise that if there is no god, then anything goes, was stated directly by Russian moral atheism philosopher Fyodor Dostoyevsky, as follows:

“If god does not exist, everything is permissible.”
Fyodor Dostoyevsky (1880), The Brothers Karamazov; view of Ivan Karamazov

(add)

Dahmer
The one person, historically, who tested out the Dostoyevsky premise, was American serial killer Jeffrey Dahmer, killing some 17 people, to satisfy his need to have men with him, the logic of which he stated as follows:

“If it all happens naturalistically? What’s the need for god? Can’t I set my own rules? Who owns me? I own myself!”
Jeffrey Dahmer (c.1993), variant of atheism belief he tried (see: killing spree paradox); as told to his father (Ѻ)

“If a person doesn’t think there is a god to be accountable to, then—then what's the point of trying to modify your behaviour to keep it within acceptable ranges? That's how I thought anyway. I always believed the theory of evolution as truth, that we all just came from the slime. When we died, you know, that was it, there is nothing ...”
— Jeffrey Dahmer (1994), interview (Ѻ) with Stone Phillips, Dateline NBC, Nov 29

(add discussion)

Kelley
In 2017, American Devin Kelley, aged 26, a former Bible study teacher (Ѻ) turned atheist, with Facebook likes of atheism cites such as the Atheist Republic and the Friendly Atheist, gunned down two-dozen plus people at the Church his second wife was teacher at.

See also
Physicochemical morality puzzles
● Robertson sin problem (Ѻ)
Slave stealing parable

References
1. (a) Winnett, Susan. (1993). Terrible Sociability: the Text of Manners in Laclos, Goethe, and James (pg. 220). Stanford University Press.
(b) Lynch, Sandra. (2005). Philosophy and Friendship (Crebillon, pg. 37). Edinburgh University Press.
(c) Steer, Alfred G. (1990). Goethe’s Elective Affinities: the Robe of Nessus (Crebillon, pg. 37; symbolically, pg. 158). Winter.
2. Bossens, David. (2013). Debates of the Hmolpedians (Amz) (Ѻ) (§Morality, pgs. 103-04). Lulu.

TDics icon ns