(Note to Peter L: This begins our discussion of metaphysical grounding and metaphysical explanation, topics of common interest. We need, over a series of posts, to uncover and discuss as many examples as we can find. My aim, and perhaps yours as well, is to demonstrate that metaphysical grounding and metaphysical explanation are legitimate topics, and that metaphysics is not a going enterprise unless they are legitimate topics. This is connected with our presumably common opposition to scientism and our presumably common defense of the autonomy of philosophy.)
Let 'Tom' name a particular tomato. Let us agree that if a predicate applies to a particular, then the predicate is true of the particular. Predicates are linguistic items. If Tom is red, then 'red' is true of Tom, and if 'red' is true of Tom, then Tom is red. This yields the material biconditional
1. Tom is red iff 'red' is true of Tom.
Now it seems to me that the following question is intelligible: Is Tom red because 'red' is true of Tom, or is 'red' true of Tom because Tom is red? 'Because' here does not have a causal sense. So the question is not whether Tom's being red causes 'red' to be true of Tom, or vice versa. So I won't speak of causation in this context. I will speak of metaphysical/ontological grounding. The question then is what grounds what, not what causes what. Does Tom's being red ground the application (the being-applied) of 'red' to Tom, or does the appplication (the being-applied) of 'red' to Tom ground Tom's being red?
I am not primarily concerned with the correct answer to this question, but with meaningfulness of the question.
Grounding is asymmetrical: if x grounds y, then y does not ground x. (It is also irreflexive and transitive.) Now if there is such a relation as grounding, then there will be a distinctive form of explanation we can call metaphysical/ontological explanation. (Grounding, though not causation, is analogous to c ausation, and metaphysical explanation, though distinct from causal explanation, is analogous to causal explanation.)
Explaining is something we do: in worlds without minds there is no explaining and there are no explanations, including metaphysical explanations. But I assume that, if there are any metaphysical grounding relations, then in every world metaphysical grounding relations obtain. (Of course, there is no grounding of the application of predicates in a world without languages and predicates, but there are other grounding relations.)
Grounding is not causation. It is not a relation between event tokens such as Jack's touching a live wire and Jack's death by electrocution. Grounding is also not a relation between propositions. It is not the relation of material implication, nor is it entailment (the necessitation of material implication), nor any other semantic relation wholly situated at the level of propositions. Propositions, let us assume, are the primary truth-bearers.
In our example, grounding is not a relation between propositions -- it is not a logical relation -- since neither Tom nor 'red' are propositions.
I want to say the following. Tom's being red grounds the correctness of the application of 'red' to Tom. 'Red' is true of Tom because (metaphysically, not causally or logically) Tom is red, and not vice versa. 'Red' is true of Tom in virtue of Tom's being red. Tom's being red is metaphysically prior to the truth of 'Tom is red' where this metaphysical priority cannot be reduced to some ordinary type of priority, whether logical, causal, temporal, or what have you. Tom's being red metaphysically accounts for the truth of 'Tom is red.'
I conclude that there is at least one type of metaphysical grounding relation, and at least one form of irreducibly metaphysical explanation.