Steve Hays responded to my comment on idealism.
One needs to distinguish between epistemological idealism (e.g. Blanshard) and metaphysical idealism (e.g. Berkeley, McTaggart).
Yes, epistemological idealism isn't as problematic.
Likewise, Blanshard’s version had more to do with his views of causal necessity and the nature of perception than the mind-dependent nature of reality (a la Berkeley).
Yes, but Blanshard didn't seem to like the idea of brute facts, which leads into circular reasoning. If each fact is dependent on the next, it seems like you end up with either an infinite regress or every fact ends up being a brute fact.
One wouldn’t get very far with a sophisticated idealist like Gödel by saying that he disconnected truth from reality. For instance, Gödel once wrote a celebrated essay for Einstein’s festschrift in which he reasoned from the theory of relativity to the static theory of time.
Some people claim Godel was influenced by idealism latter in life. But Godel's views seem paradoxical, since his "second plane of reality" seems to be an attempt to harmonize idealism and realism. Not that I would expect all idealists to agree with me just because I say they disconnect truth and reality; but will you be unsurprised if John Loftus is absent from Church this week, dispite your work on the Infidel's Delusion?
Likewise, quantum mechanics is often cited in support of idealism. In addition, there are scientists like David Bohm, and Rupert Sheldrake who incline to panpsychism because they think that’s where the empirical evidence leads. In a similar vein, David Chalmers and John Leslie are quite sympathetic to panpsychism.
They may be scientists but they are getting into metaphysics when they go that far. As Aquinas says:
"As other sciences do not argue in proof of their principles, but argue from their principles to demonstrate other truths in these sciences: so this doctrine does not argue in proof of its principles, which are the articles of faith, but from them it goes on to prove something else; as the Apostle from the resurrection of Christ argues in proof of the general resurrection (1 Corinthians 15). However, it is to be borne in mind, in regard to the philosophical sciences, that the inferior sciences neither prove their principles nor dispute with those who deny them, but leave this to a higher science; whereas the highest of them, viz. metaphysics, can dispute with one who denies its principles, if only the opponent will make some concession; but if he concede nothing, it can have no dispute with him, though it can answer his objections." (link)
While I don’t think the coherence theory of truth is a sufficient stand-alone theory of truth, I think the coherence theory of truth has its place in dualism. Just as the correspondence theory dovetails with concrete truths of fact, the coherence theory dovetails with abstract truths of reason. The correspondence theory works well enough for empirical data, but it’s unsuited to abstract objects like mathematical truths and logical relations.
I am open to blending the two, but at first glance I don't see why we need the coherence theory if we can say things like the laws of logic correspond to the way God's mind works or something of the sort.
It’s also the case that even physical reality begins in the mind–the mind of God. The material world has its origin in the idea of the material world. God’s exemplary concept. So idealism is true to some degree, even if it fails to capture the whole truth.
If that's all idealism meant, it would be harmless.
To say that “consciousness observes reality” is only “self-evident” if you take direct realism to be self-evident. Since direct realism is eminently disputable, you’ve overstated your case.
The amount of dispute isn't all that relevant, but assuming the disagreement between direct/indirect realists is substantive, not just semantic, the two groups simply have slightly different axioms.
When I ascribe a modified coherence theory of truth to Van Til, this is what I mean. Van Til had a position which was structurally similar to epistemological idealism in the following respect: he viewed truth in holistic terms.
And this is because, as a Calvinist, he regarded every event as a meaningful event. Every event had a purpose in the plan of God. There were no brute facts. No discrete, surd events. Each event was related to every other event, for God intended each event, and–what is more–he intended each event to contribute to a meaningful and fully-integrated totality, in a part/whole relation.
When denying brute facts, the issue isn't that facts are related or that truths don't contradiction or that God has a plan for everything. Rather, the epistemological question is how we know a given fact is true? Since brute facts or axioms are usually used as the basis for proving other things, denying brute facts does take out one of the major ways people have gone about proving anything. So denying brute facts is one of the reasons Van Til has been accused of scepticism.