This is what we do when we conduct experiments. This stands in contrast to empiricist scientists' claim that all scientists can do is observe the relationship between cause and effect and impose meaning. Whilst empiricism, and positivism more generally, locate causal relationships at the level of events, critical realism locates them at the level of the generative mechanism, arguing that causal relationships are irreducible to empirical constant conjunctions of David Hume's doctrine; in other words, a constant conjunctive relationship between events is neither sufficient nor even necessary to establish a causal relationship.[5]