Nagel’s Omission of Theology as a Mode of Theoretical Knowledge

(Last Revised May 20, 2017}

I have already devoted two posts in the present series, the “Nagel’s Comparison and Contrasting of Philosophy and Science,” of April 12, 2016, and the “Nagel’s Comparison and Contrasting of Philosophy and Mathematics,” of April 19, 2016, to an understanding of one telling passage in the opening chapter of Thomas Nagel’s concise introduction to philosophy,*  What Does It All Mean? Further reflection upon the passage, however, tells me that at least one more delving into it will be helpful to the understanding of his scheme of things.

That passage reads (p. 4):

Philosophy is different from science and from mathematics. Unlike science it doesn’t rely on experiments or observations, but only on thought. And unlike mathematics, it has no formal methods of proof. It is done just by asking questions, arguing, trying out ideas and thinking of possible arguments against them, and wondering how our concepts really work.

He has here recognized the existence of three distinct modes of theoretical knowledge, those of science, mathematics, and philosophy. And he has contrasted them. Reading just a bit between the lines, we can discern that, in his view, science differs from mathematics and philosophy in that it relies on experimentation and observation, while they rely on thought and not on experimentation and observation. In turn, mathematics differs from philosophy in that the former possesses “formal methods of proof,” while the latter does not. One might infer that it is Nagel’s view that, while in mathematics we can prove propositions to be true, in philosophy there are no such proofs; in a post to come in the near future, I plan to offer evidence that that is indeed the case.

But the purpose of today’s post is that of drawing attention to and reflecting upon the fact that Nagel’s contrasting of science, mathematics, and philosophy has not included one type of theoretical knowledge, theology, that at least some major thinkers, contemporaneous as well as past, have thought it necessary to extend recognition to.

There is, however, a distinction that needs to be made here between two senses of “theology.” There is, that is, at least in the minds of some of these thinkers, a theology that is a philosophical or natural theology, on the one hand, and a theology that is a supra-philosophical or supernatural theology, on the other.

We can identify philosophical theology as a natural theology because, as a philosophical theology, it is a part of philosophy, that part of philosophy that concerns itself with the existence and the nature of the divine: Does anything divine exist and, if so, what is it? But philosophy is a theoretical discipline that relies exclusively upon strictly human means of attaining knowledge, that is, the means of attaining knowledge that are natural to humans, i.e., that belong to humans by nature. These means include, for, say, philosophers in the Aristotelian tradition of philosophy, both observation, involving our senses, and thought, the activity of our intellect; for some other philosophers, philosophy has to rely on thought alone, ceding to science the use of observation as a means of knowledge.

Yet in either case, the means of knowledge afforded to philosophy, and so to philosophical theology, is or are purely natural. In the case, however, of the supra-philosophical or supernatural theology to which some major thinkers extend a recognition, the knowledge of the existence and nature of the divine is not achieved uniquely by purely natural human means; rather, they hold, at least some humans benefit from a divine grace elevating the natural human means of knowledge to a supernatural level, a level above and beyond the natural.

In the two previous posts mentioned above I observed that Nagel has thus far in the book not offered any arguments on behalf either of his thesis that philosophy does not rely on experiments or observations or any on behalf of his thesis that it is not a demonstrative science. I will now observe that that thus far in the book he has not offered offered one justifying his non-inclusion of theology, whether natural theology or supernatural theology, among the theoretical disciplines to be compared and contrasted.

Now one might well ask whether the author of a book bearing the subtitle, A Very Short Introduction to Philosophy, should be expected to include demonstrations of all of his theses. The answer, of course, would be, “No.” But one could still go on to add that perhaps a better subtitle of the present book would have been, A Too Short Introduction to Philosophy.

Until next time.


*Thomas Nagel, What Does It All Mean? A Very Short Introduction to Philosophy (New York and Oxford: Oxford University Press, 1987). The book is readily available for purchase through You need only click on the following image to be taken to the Amazon site:


Today’s post is one in the series, focusing now on Thomas Nagel’s What Does It All Mean? A Very Short Introduction to Philosophy,* that constitutes the Introduction to Philosophy Initiative introduced in “Announcing the After Aristotle Introduction to Philosophy Initiative.”

There is a post, “Table of Contents,” listing the titles of and links to the posts published in the series, at:

The “Table of Contents” for the “After Aristotle Introduction to Philosophy Initiative”



About Rchard E. Hennessey

See above, "About the Author/Editor."
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