A self-limiting reason… is an amputated reason. If man cannot use his reason to ask about the essential things in his life, where he comes from and where he is going, about what he should do and may do, about living and dying, but has to leave these decisive questions to feeling, divorced from reason, then he is not elevating reason but dishonoring it.
Truth and Tolerance, 158
Reflection – When Ratzinger talks about a ‘self-limiting’ reason, he is referring to the philosophical position known as logical positivism. This is the all-too-familiar insistence that the only things we can know and reason about are immediate sensory phenomena, controlled scientific experiments on these, and the logical truths of mathematics.
Everything else is out of bounds—mere emotion or sentiment. So that means that not only God and the soul are sentimental notions, but little things like… oh, I don’t know, love, justice, peace, friendship, good and evil, happiness. Little details like that—nothing important!
All of that is utterly beyond the scope of reason, according to strict logical positivism. Anything we say about those matters is strictly how we feel about them, not any real statement about reality.
Now, logical positivism sounds convincing to many people, especially people who are trained in the hard sciences. We know that experimental science yields hard facts about reality, when done correctly. We know this because…well, because science works! It leads to technological applications that do what the scientific experiment says they should do.
So knowing that we truly do know stuff through science and math, it is understandable to say that any other kind of knowing is not-really-knowing. There is no scientific experiment that will prove what friendship is, or justice, or love. Or that your spouse loves you, for that matter (‘honey, could you please step into this test tube for a minute? No, I can’t tell you why…’). You can't weigh your spouse on a scale... or at least it is not conducive to domestic harmony to try.
There is also no scientific experiment that can prove the truth of logical positivism. And this is the key point. By its own standards, it is self-refuting. Truth = math and hard science, right? That’s the hard stance of the positivist. But there is no and can be no mathematical equation or hard scientific experiment that can prove that positivism is true.
So it collapses—goodbye logical positivism! Thanks for playing!—and reason can expand out, as it always has, to all the deep questions about life and its meaning, good and evil, God and the soul. Hurray! The beautiful truth is, we are made to reach out with our minds and hearts both to these deepest matters, made to truly know, or at least truly search for true knowledge of all of these things.
Logical positivism reflects a certain despair in the possibility of knowledge of truth, or perhaps a certain dark desire to push away the truths that our reason might lead us to, in favor of being able to do whatever we please. But we are made for better things, made for a true encounter, a true dialogue with reality that will lead us out of our own self-enclosed worlds into broader fields of meaning and life. In short, the truth will set us free.