It is often held that something has value only in virtue of being valued by some evaluative being: value is conferred on something by the attitude of valuing. This is supposed to be true even of pleasure. But is the act of valuing itself something that has value? If not, it is hard to see how it could confer value on other things. But if it does have value, then it must do so in virtue of some further act of valuing. Then that valuing in turn must either lack value or have it in virtue of a further act of valuing. An infinite regress results from the latter horn of the dilemma. Therefore, not all value can be had in virtue of acts or attitudes of valuing. Pleasure, for example, is valuable in itself, irrespective of whether anyone regards it as valuable.
Some superpowerful aliens arrive one day and offer to ship us off to their galaxy if we’d like. It’s really nice there, they assure us, and they have the photographs to prove it. Our standard of living will go up at least 20% and we can all live at the beach. But if we accept they will have to destroy planet earth (something about an intergalactic highway they’re building)–the choice is ours. We can take all the animals with us, if we prefer; transportation isn’t a problem. We decide to take them up on their offer. As we leave earth in their spacious space ship we watch as a planet-sized jet of flame incinerates earth behind us. The oceans instantly evaporate, the atmosphere blows away, all traces of life are destroyed; what remains is a smoking expanse of melted rubble. And it will stay like this for all eternity. Wouldn’t you feel bad about about this act of cosmic vandalism? Wouldn’t you feel you had done something wrong? Something of great value had been destroyed–something of beauty, interest, and fecundity (see my Climate Change entry). This shows that the earth is valuable for reasons that transcend its instrumental value to us.
If physics needs an interpretation, in rather the way a formal language does, if it is to be meaningful, doesn’t that show that metaphysics is indispensable? Physical knowledge can’t be all the knowledge there is, because the formulas of physics stand in need of interpretation. Are electrons continuant particulars or are they just sequences of events? Are there categorical properties lurking behind the dispositions to motion we observe? Are particles really nothing but fields? Is consciousness present even at the most fundamental level? Physics itself doesn’t answer these questions, so that complete knowledge of the physical world requires metaphysical knowledge in addition to physical knowledge in the strict sense. You can’t know the nature of the physical world by knowing physics alone.