I'm not sure but perhaps this may help you
In parallelism, mental events and physical events are perfectly coordinated by God; so that when a mental event such as Sally's decision to walk across the room occurs, simultaneously Sally's body heads across the room, in the absence of a direct cause-effect relation between mind and body. Mental and physical events are just perfectly coordinated by God, either in advance (as per Gottfried Leibniz's idea of pre-established harmony) or at the time (as in the Occasionalism of Nicolas Malebranche).
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Otherwise parallelism can be a rhetorical concept.