Much ink has been spilled on the question of the nature of the relationship between science and religion. Most writings in this area can probably be classed as either attacks on religion's perceived encroachments on the scientific realm or apologetics for religion's insistence on knowing better than scientists — sometimes even in fields of scientific endeavor. Not everything is quite so polarized as this division sounds, but it describes the general trends well enough.
It is, then, refreshing to find someone who attempts to transcend the division. I believe that this is what we see Paul Tillich doing here:
The distinction between the truth of faith and the truth of science leads to a warning, directed to theologians, not to use recent scientific discoveries to confirm the truth of faith. Microphysics have undercut some scientific hypotheses concerning the calculability of the universe.
The theory of quantum and the principle of indeterminacy have had this effect. Immediately religious writers use these insights for the confirmation of their own ideas of human freedom, divine creativity, and miracles. But there is no justification for such a procedure at all, neither from the point of view of physics nor from the point of view of religion.
The physical theories referred to have no direct relation to the infinitely complex phenomenon of human freedom, and the emission of power in quantums has direct relation to the meaning of miracles.... The truth of faith cannot be confirmed by latest physical or biological or psychological discoveries—as it cannot be denied by them.
- Paul Tillich, “The Truth of Faith,” Dynamics of Faith (1958)
As a theologian there is no question where his sympathies lie in the debate between science and religion; nevertheless he is honest enough not to give in to the temptation to use science inappropriately in the effort to defend religion or his religious beliefs.
Tillich is making a point here which, I think, is argued far more often by scientists than by defenders of religion: not everything discovered by science necessarily validates the tenets of ancient religions and, in fact, you shouldn't go around expecting anything different.
It's a relatively common today to see theologians and religious apologists claiming that some recent theory or discovery in science "proves" some religious belief (most commonly the existence of God) and, therefore, scientists are finally coming around to where theologians have been sitting all along. I wonder how common it was to see this in Tillich's day, if he felt it necessary to speak out against it?
Truth of Faith?
I believe that it is important to pay attention to the fact that Tillich uses the phrase "truth of faith" rather than "truth of religion" or "truth of religious doctrines." Although it is common for "faith" to be used as a synonym for "religion" in colloquial language, I don't believe that this is what he is doing. Instead, I think that Tillich is drawing our attention to the fact that we aren't simply dealing with abstract doctrines of religion but, rather, objects of faith.
Does this matter? Yes, it should — especially in the Christian context where so much emphasis is placed on both the importance and the moral qualities of having "faith" in Christianity. After all, if Christianity is something that a person is supposed to adhere to because of "faith" in things that are "unseen," how can they even care much about whether science "proves" faith at all? As a matter of fact, it can be argued that if Christianity really must be held to through faith, then it isn't even possible for science to prove it — and that's exactly what Tillich claims.
If someone's "faith" were subject to proof then the objects of their faith are more properly the objects of scientific scrutiny and investigation. One doesn't talk about the mass of an oxygen atom or the distance between Earth and the Moon as objects of "faith," right? Insisting on "proving" the truth of faith-claims blurs the lines between science and religion, and not to the benefit of religion.
Proof & Disproof
We must remember that if something is subject to "proof" by science, then it is also necessarily subject to "disproof" in the same manner as anything else studied in science. This isn't normally an absolute sort of disproof; instead, it's "disproof" in the sense that if a claim fails to be supported by the evidence and is contradicted by sufficient counter-evidence, then not only is it unreasonable to believe it but we should actively deny it (at least until significant contradictory evidence arrives).
Generally speaking, religious believers object to their beliefs being subject to such scrutiny — they insist that religion cannot be disproven by science, just as Tillich does. They cannot, however, insist upon this while also insisting that their religion can and has been proven by science. If you take one, then you have to take the other.
I believe that Paul Tillich is right in that "faith" isn't supposed to be subject to proof or disproof, at least according to the way believers tend to define the term. I do not agree, however, that this is necessarily appropriate. You can't simply say that something is an "object of faith" and thereby deny it critical scrutiny. Faith is not and cannot be a "get out of jail free" card for one's beliefs, opinions, ideas, or claims.
When a religion makes empirical claims, it renders those claims subject to proof or disproof. The only way for the "faith" of a religion might be fairly exempted from the critical scrutiny of science is for it to refrain from making claims that might be directly subject to empirical testing or logical analysis. Just how likely is that, however? Not very, at least as far as I can tell.
Despite this, it would be a nice change if believers didn't attempt to latch on to every latest finding of biology of physics in an attempt to "prove" the truth of what they typically insist requires "faith" then turn around and deny that some new finding can't possibly "disprove" their religious beliefs. A little consistency here isn't too much to ask for.
