Both idealism and the coherence theory of truth disconnect truth from reality. They confuse the ontological question of "why is this true?" with the epistemological question of "how do we know?" In the process they loose sight of the self-evident principle that cannot be rationally denied that consciousness observes reality.
Since I’m not an idealist, I could let this slide. However, the objection is so problematic, both on its own terms, and in relation to Van Til, that I’ll venture a few comments.
1.It’s odd that you’d classify idealism as a form of scepticism when idealists tend to be rationalists (e.g. Blanshard, Leibniz, McTaggart).
2.One needs to distinguish between epistemological idealism (e.g. Blanshard) and metaphysical idealism (e.g. Berkeley, McTaggart).
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).
3.Although idealism and the coherence theory of truth often go together, they are not inseparable.
4.Since I’m not an idealist, I’m in partial agreement with you that idealism (a la Berkeley) disconnects truth from reality. At the same time, that’s how a non-idealist views idealism.
In the nature of the case, an idealist doesn’t view himself as disconnecting truth from reality. To the contrary, for him, the rational is the real, and vice versa.
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. 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.
That’s not my own interpretation of reality, but proponents sometimes draw attention to experience or phenomena which any comprehensive worldview must integrate one way or another.
Again, I don’t say this to defend idealism or panpsychism (which I reject). I’m just making the point that an idealist is aware of all the same phenomena that the opposing positions are aware of. He can square appearance with his understanding of reality. Indeed, he happens to think that his position has more explanatory power than the competition. And he’d say it’s the nonidealist who is guilty of dichotomizing truth and reality. You wouldn’t make much headway with an astute idealist like Timothy Sprigge by pointing to “reality”–as if his own theory is oblivious to reality.
5.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.
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.
7.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.
6.Gordon Clark was arguably closer to idealism than Van Til. Clark was a big fan of Blanshard. And the position of later Clark is hard to distinguish from pantheistic idealism.
By contrast, Van Til criticized Clark’s rejection of sense knowledge for failing to do justice to natural revelation. Van Til was a scientific realist, whereas Clark was a scientific antirealist.
7.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.
In that respect, it’s analogous to a system of internal relations. However, unlike some idealists (e.g. McTaggart), Van Til was not a necessitarian. He didn’t collapse truths of fact into truths of reason. Truths of fact were contingent truths, contingent on God’s decree. What is more, God freely decreed the world.