 Perhaps the most influential argument for the claim that causal notions cannot play a legitimate role in physics appeals to the fact that the causal relation is generally understood to be asymmetric. This asymmetry is often assumed to coincide with a temporal asymmetry according to which effects do not precede their  causes.[4]  This gives rise to the time asymmetry challenge that contrasts the time-asymmetry of causal relations with the purported fact that physical laws make no distinction between the past and future direction. This contrast is offered as a reason for why causal relations cannot be a part of physical theorizing. The time-asymmetry challenge can be represented in premise-conclusion form as follows: