  The role of simplicity in Humean views is important for randomness. For if a world contains a genuinely random sequence of outcomes, there will be no short description of that sequence. Those descriptions which do not attempt to describe what happens in all its particularity, but instead involve a probability distribution that makes the sequence a typical one with respect to that probability function, will be less informative but much shorter, and still fit just as well. So it seems that if a world contains a random sequence of outcomes, the best theory will be one which involves probabilities, and in virtue of being part of the best theory, those probabilities will be chances. That makes the right to left direction of RCT plausible. The other direction would hold if this route through simplicity was the only way in which chances could enter into the best system. Could there be a world with chances in which there was no random sequence? Here things are rather murkier for the Humean. For the hallmark of the best systems approach to chance is that, by involving simplicity, it avoids some of the problems for pure frequentism. In particular, an unrepresentative outcome sequence (a short one, or highly biased one) need not force the chances to take the value of the actual frequencies. Suppose a world contains two intrinsic duplicate coins, one of which is tossed many times, landing heads about half the time; the other is tossed few times and lands tails every time. The second coin’s outcome sequence has a heads frequency of zero. It is a strength of the best systems account that we may still say the chance of heads was \(\frac{1}{2}\), because the coin is embedded in a world where another, similar, coin did have the appropriate outcome frequencies, and it is overall a simpler theory to say that both of these coins obeyed the same probabilistic laws than that the second one was an oasis of determinism. But this case provides a problem for RCT—it looks like the second coin toss is not part of any random sequence of outcomes (since a few all tails tosses is not random), but it has a chance.