Opposition to determinism promotes that without belief in uncaused free will, humans will not have reason to behave ethically. Determinism, however, does not negate emotions and reason of a person, but simply proposes the source of what causes us to fall back on moral behavior. Anyone susceptible to immoral actions from the idea of determinism was susceptible before and does not hold strong moral judgment prior to the idea.
Determinism implies the moral differences between two people are caused by hereditary predispositions and environmental effects and events. Simply because the cause of a person’s morality (depending on the branch of determinism) is not entirely themselves, this does not mean determinists are against punishment of people who commit crimes: independent of moral judgement, punishment can still serve to modify a person’s behaviour.
Another point of view is that if determinism is true, and free will is not, then morality and ethics are meaningless concepts. Morality and ethics require that a choice can be made in order for these concepts to have any meaning. But if a person has no choice, in the case of a deterministic world with no free will, then it does not make sense to say whether individuals can make more (or less) ethical or moral choices, because there are no options available to them except the one they must deterministically follow.
I will use the words determinism and causality interchangeably to mean approximately the same thing, with determinism referring to the more general state of the world and causality referring to more specific causal relationships.
On the other hand, Sam has argued that morality can be studied scientifically. This would require operationally defining “morality” (Harris suggests a definition akin to “a behavior’s probability of maximizing human wellbeing” but the definition itself is not the focus of his argument). Harris goes on to suggest that, given that human brains have certain properties, we could go on to identify objectively superior moral frameworks; that is, multiple “optimized” ethical systems may emerge that satisfy our definition of moral.