 Given this understanding of the core improbability claim, some critics (e.g., Carlson and Olsson 1998) have argued that the fine-tuning at issue requires no explanation. Any specific sequence of heads and tails in a long series of coin tosses is improbable in this sense; that is, any one sequence would be one we wouldn’t and shouldn’t expect. But no specific sequence requires an explanation other than that it was randomly generated. So why should the finely-tuned actual array of constants, laws, and initial conditions require an explanation other than an appeal to randomness? Many, however, disagree, and argue that the availability of explanatory hypotheses with intuitive pull, such as an intelligent designer or a multiverse (discussed below), indicates that a more substantive explanation for fine-tuning is required (e.g., Leslie 1989).