The subject-summing problem, and indeed all forms of the combination problem, can be construed in a stronger or a milder form. In its milder form it is taken to be a challenge that the panpsychist must address in the long run, either by eventually coming up with an adequate theoretical account of mental combination, or at least by explaining why such an account is beyond our ken. Almost all panpsychists accept this challenge, and one major activity of the contemporary panpsychism research project is attempting to solve (or circumnavigate) the subject-summing problem and the combination problem more generally.