Epistemology: Peter Kreeft’s Summa Philosophica Part VI

Why did God create us? She is the mystery!
Why did God create us? She is the mystery!
Read Part V.

Remember, we’re doing summaries of summaries here; only bare sketches are possible. Buy his book for more detail.

We are back on familiar stamping groups with Question VI, Epistemology. Directly related to probability and statistics, this stuff. So brighten up! See at least the summary in Article 2.

This is the last of the foundational meaty tough stuff. Next time we we’re on to the more succulent material: ethics.

Article 1: Whether Skepticism is refutable?

Oh, yes. The basic objection is that even the most uncontroversial syllogism must rest on premises that themselves have to be proved. And if those are proved, it is because they rest on still further, more basic premises, which also have to be proved, seemingly ad infinitum. And then even the workings of the syllogism itself—why is it that the conclusion follows—must be proved, etc.

As Aristotle showed, this “backward doubt” terminates in two places: psychologically indubitable immediate sense experience and logically indubitable first principles such as “X is not non-X” in theoretical thinking and “Good is to be done and evil to be avoided” in practical thinking.

Another way, with Pascal, to say “indubitable” is “by faith.” All who claim to be skeptics lie (at least to themselves). “To practice skepticism is to cease to speak, like Cratylus, who would only move his finger.” And even that’s cheating.

Article 2: Whether truth is objective?

Yes. If you think not, tell any professor “Evolution is false.” You will quickly learn not only is there objective truth, but that some truths are sacred.

[I]f all truth were subjective, then that truth also would be subjective. But what is subjective is changeable and uncertain. Therefore if all truth were subjective, it would be changeable and uncertain, and thus that “truth” also—that all truth is changeable and uncertain—would be changeable and uncertain. But what is uncertain may be false, and what is changeable can be changed. Therefore the “truth” that all truth is subjective, is uncertain, and may be false; and it is changeable, and can be changed—and if changed, then changed to “truth is objective.”

What’s true for thee, is true for me, baby, and vicey verso. Truth is “thinking and saying what is” (Aristotle, again). It’s not “what works” or the “coherence of ideas with each other.” And it certainly isn’t idealism. I love this checklist-summary so much, that I can’t resist quoting it all (but still buy the book!):

(1) Is this thing real?

(2) If so, do I, or do we, or can I, or can we, know that this thing is real?

(3) If so, is that knowledge certain rather than merely probable?

(4) If so, can I convince others of that certainty by rational arguments?

(5) If so, does the argument use the scientific method?

A thing can be real without being known.

A thing can be known without being known with certainty.

A certainty can be private rather than demonstrable.

And proof or demonstration may use other methods than the scientific method.

Confusion between (1) and (2) produces philosophical idealism.

Confusion between (2) and (3) produces skepticism or probabilism.

Confusion between (3) and (4) produce subjectivism.

And confusion between (4) and (5) produce scientism

Article 3: Whether we know things-in-themselves?

Yes. Though Kant said we can’t. I’ll only point you to David Stove’s famous contest to identify the worst argument in the world (see Jim Franklin’s page, or this PDF). Here’s the stinker:

We can know things only {as they are related to us; under our forms of perception & understanding; in so far as they fall under our conceptual schemes etc.}

So: We cannot know things as they are in themselves.

Article 4: Whether appearance coincides with reality?

No. We need the distinction of what is “true (in which appearances faithfully coincide with reality) and the false (in which appearances deceive because they fail thus to coincide with reality).”

To ask (1) what a thing is, (2) whether it is, or (3) why it is, is to express the will to know what is true; and this is to assume that there are both true and false, i.e. real and only apparent, answers to those questions, and thus that appearance and reality are not identical.

“In order to judge appearances, we must know something more than appearances.” Which is to say, reality.

Article 5: Whether all ordinary (natural) human knowledge begins with sense experience?

Yes. Though it seems we know tidbits like “X=X, that 2+2=4, and that if it is true that X is, then it is false that X is not” without benefit of sense experience.

On the other hand, “The blind have no innate idea of color, nor the deaf of sounds.” And we “must distinguish the claim that all our knowledge begins with sense experience from the claim that it is limited to it” which is false.

We don’t learn tautologies like X=X “unless we fist experience some things through the senses and only then rise to such principles by abstraction and inductive reasoning. It is not infants but philosophers who formulate such tautologies.”

Article 6: Whether there is a priori knowledge?

Yes. But didn’t we just agree “that all knowledge begins with sense experience, which is another way of saying that all knowledge is a posteriori knowledge”? Maybe a stronger objection:

If there is a process of thinking that leads from a posteriori knowledge of sensed particulars to a priori knowledge of understood universals, it is invalid; for it is invalid to conclude to a universal merely from particulars. “All men are mortal” does not follow from “this man is mortal” or “these men are mortal” or “some men are mortal.”

Yet there “is no contradiction between saying that all our knowledge begins with sense experience and saying that from sense experience we can rise to knowledge that does not depend on sense experience” which is a priori knowledge.

The process is not first of all one of inductive reasoning…but the understanding…of a universal which we find embedded in sensory particulars and which we abstract from those particulars…We can distinguish necessary and essential features of human nature (e.g. mind and body) from contingent and accidental ones (e.g. race and gender), but abstracting the former from the latter…Thus our knowledge that all men are mortal is a priori knowledge, known with certainty even prior to observing everyone die, but it emerges only from abstraction from experience which is a posteriori and empirical.

Stove (again!) shows the difficulty begins with improper use of inductive, which is now unfortunately taken to mean all non-deductive reasoning, instead of solely the type which leads to universals. Not for the first time I recommend his Rationality of Induction.

Article 7: Whether ideas are the immediate object of knowing?

No. Idealism, as we have long agreed, is deader than Marley. Kreeft slips in a joke. “[I]f the objects of our thinking were ideas, all sciences would be subdivisions of psychology. (Perhaps some psychologists would not regard this as a reductio ad absurdum.)”

Another opportunity to push Stove: see his essay “Idealism: A Victorian Horror Story”, reproduced in many places.

Article 8: Whether certain knowledge is possible?

Yes. And if you say no, you say yes, so you must say yes. And if you say maybe, you also say yes. Put up any fight at all and you say yes. Thus, yes.

Examples of certainty? Non-contradiction, whatever comes to be is caused (God does not come to be, therefore is not caused, thus He can be the uncaused first cause). Again, try the “evolution false” gag at your nearest college campus. Or try to write a blog post about which every reader agrees (the temptation is to say it certainly cannot be done).

Article 9: Whether the essential questions of philosophy are “mysteries”?

Yes. Mysteries not in the sense of whodunnits, but are thought puzzles in the sense of nobody knows, or can know, their whys. Not to beat you over the head with Stove, but in Rationality he has a lovely essay explaining that it is senseless to ask how something which is necessarily true is true.

Why is it true that “X=X” (or pick your favorite axiom)? I don’t know, and you don’t either: it’s a mystery. It’s just true. The terms is broader than this, though:

Marcel defines a “mystery” as distinct from a mere “problem,” as “a problem that encroaches upon its own data,” i.e. a question which so involves the very being and life of the questioner that it is impossible, and even undesirable and misleading to have total detachment and objectivity, as is required in the sciences.

Incidentally, many (not all) “problems” in philosophy aren’t. They are called so because the natural conclusion derived from cherished premises is unacceptable, or a conclusion is believed but can’t be derived from acceptable premises.

Article 10: Whether we can have knowledge of mysteries such as God, freedom, immortality, morality, and the meaning (purpose) of life?


[I]f we have no knowledge of [mysteries], how do we know them well enough to know that we have no knowledge of them? For instance, how can we know God so well that we know we cannot know Him at all? Is not such skepticism, like all skepticism, ultimately both self-contradictory and arrogant?

It’s as well to leave off with another shade of faith.

Religious faith is not the same as opinion. For faith, whether true or false, is a human response to a divine revelation, like light reflected in a faithful mirror, and thus its content is in itself most certain, even if not logically provable, for God can neither deceive nor be deceived; while mere opinion rests on the uncertainty of the human mind alone.

Faith is not (always) identical with intellectual belief.

Read Part VII.


  1. William Sears

    I claim that we are all agnostics (skeptics or even relativists) at heart since even the most devout has occasional doubts. The fact that we are inconsistent in our lack of absolute belief (i.e. a hypocrite) does not make the position wrong (see your previous article). I think that the same could also be said of scientism, although I still do not know what you mean by that term.

    As to the above, the devil made me do it.

  2. Ye Olde Statistician

    Wm Sears: scientism, although I still do not know what you mean by that term.

    “Scientism is the view that all real knowledge is scientific knowledge—that there is no reliably objective, rational form of inquiry that is not a branch of science.”


    “Of course, from the very beginning of the modern scientific enterprise, there have been scientists and philosophers who have been so impressed with the ability of the natural sciences to advance knowledge that they have asserted that these sciences are the only valid way of seeking knowledge in any field. … This position has been called scientism — a term that was originally intended to be pejorative but has been claimed as a badge of honor by some of its most vocal proponents.”
    “The Folly of Scientism,” Austin L. Hughes, Carolina Distinguished Professor of Biological Sciences at the University of South Carolina.

    See also:

    The origin of the term has been ascribed variously to Popper, Hayek, Feyerabend, Putnam, Rothman, et al. (For some reason, devotees of the genetic fallacy have insisted it was coined by “religious believers.”)

  3. Briggs


    What a great find!

    If any human institution is held to be exempt from the petty, self-serving, and corrupting motivations that plague us all, the result will almost inevitably be the creation of a priestly caste demanding adulation and required to answer to no one but itself.


    There seems to be a thirst for this kind of explanation, but the pop evolutionary psychologists generally pay little attention to the philosophical issues raised by their evolutionary scenarios. Most obviously, if “we now know” that the selfish behavior attributed to our ancestors is morally reprehensible, how have “we” come to know this? What basis do we have for saying that anything is wrong at all if our behaviors are no more than the consequence of past natural selection? And if we desire to be morally better than our ancestors were, are we even free to do so? Or are we programmed to behave in a certain way that we now, for some reason, have come to deplore?

  4. William Sears


    What you have given me is a dictionary definition of scientism, of which I am fully aware. What I asked for is what Briggs means when he uses that term, which only he can answer. I was also speaking tongue in cheek. I usually take the position that I will never explain my jokes, but there you go.

    But more seriously: the problem with the dictionary definition of scientism is that the term science simply refers to organized knowledge. So the objection to it must ask for a consideration of disorganized knowledge or revelation as a source of knowledge. I do not necessarily object to such claims but I think that they should be stated honestly rather than hiding behind accusations of scientism. If the objection was that some people claim that all knowledge must fall under the purview of physics and chemistry alone, then I would agree that this would be far too limiting. But the term scientism is much too broad and I suspect that its use is dishonest. But, that’s just me.

  5. Ye Olde Statistician

    Surely you must realize that in current usage “science” means “natural science,” not military science, political science, theological science, etc. Go on, ask Dawkins if when he praised the virtues of science, he is thinking of political science.

  6. William Sears


    How do you know that Briggs means “natural science” when he uses the term scientism? Also, what does Dawkins have to do with the issue? Will he know what Briggs means?

    Less facetiously, you should defend your own use of the term “scientism” not Briggs. A dictionary definition is not sufficient. I would like to see a justification of the term. I have said in a previous post that I believe that the term is nothing but misdirection and used to avoid justifying personal and idiosyncratic beliefs that one would prefer not be subjected to scientific scrutiny. I have asked for examples of truths that one can only obtain by non-scientific methods, but have never gotten a serious response. I only hear vague statements about love and beauty or higher truths.

    I have scanned your links, but they do not seem to give any examples either but use the term to complain about what they call (or should call) scientific hubris. Of course, I may have missed something. Finally, the hubris of individual scientists certainly exists, so call it by name and do not invent what I think is a meaningless term “scientism”.

  7. Ye Olde Statistician

    I have asked for examples of truths that one can only obtain by non-scientific methods

    That an empirical universe exists cannot be obtained by scientific means, since one can rely on empirical evidence only if one assumes a prioi that an empirical universe exists.

    That the universe is lawful cannot be obtained by scientific means, since science must assume a priori that the universe is lawful, and no universal can be concluded from any finite number of particular examples.

    That the value of pi is irrational cannot be obtained by scientific means, since any empirical measure of the circumference and diameter of material circles will be finite and C/d will always therefore be ratio-nal.

    That you regard love, truth, beauty and the like as “vague” is a marker for scientism.

    Scientific hubris will do for the attitude of any particular scientist of (more often) science fanboy. Scientism will do for the concept as such, since English tends to add “-ism” to nouns for such purposes: e.g., creation-ism, futur[e]-ism, commun[e]-ism, creation-ism, Marx-ism, national-ism, imperial-ism, etc. The atheist Michael Ruse has made a distinction between creation/creationism and between evolution/evolutionism for precisely this reason: some people make an apotheosis of an idea, by making it an -ism. (You may suggest scienc[e]ism as an alternative formation, although “scientist” and “scientific” indicate the tendency of soft-c to morph into t at such junctures.)

    In any case, the meaning of the term does not in fact depend on whether Matt Briggs or Karl Popper uses it.

    See also: http://www.amazon.com/Philosophy-Bundle-RC-Routledge-Classics/dp/0415610249 for an indepth discussion.

  8. Sander van der Wal

    The Faith definition doesn’t work, because you do not know whether the reflection is of the true divinity, or one of the many fake ones that must be the things seen by people believing the other religions.

  9. Sander van der Wal


    I experience the Universe. I have now two choices: hypothesize it is made up my myself, Solipsism, or hypothesize it is real.

    The universe appears as if it is working according to certain rules. I can now hypothesize that the Universe does indeed works according to certain rules, and they start hypothesizing about what these rules are (examples, Newtonian Gravitation, Maxwellian Electomagnetism, General Relativity, Quantum Electrodynamics, Evolution).

    Science doesn’t need a Universe with rules, but without a Universe with rules, there probably would be nobody to work out what the rules are, there not being enough consistency to have actors with the brainpower to work out the rules.

    The concepts are vague because the way it is used. I know about love, beauty and truth, because having experienced, observed, it. But as I do not agree with everybody else on which people, processes and things are beautiful, it is clear that at least a part of beauty lies with me.

    Not so with truth. I believe that certain theories are true, and I know that certain facts are true (having experienced them, and being able to re-experience them). Better said, I believe that certain theories are describing the real (non-solipsist) world as it is, and that certain facts have happened. Then I can put the theories and the facts in logical statements, which can be true, or false.

    Like the theory “all men are mortal”, the observation “Socrates is a man” and the prediction “Socrates is mortal”, which can be observed by watching Socrates die after drinking the poison.

  10. William Sears

    YOS & Briggs,

    I assume that you are presenting your best examples, which I believe are all flawed for the following reasons.

    Empirical Universe: The fact that one must assume the ability to make observations before one makes them is an extremely weak criticism. But more importantly, this must be done by any approach whether scientific or not. Therefore this is not an example of a non-scientific method that does what science can not. Exactly the same problem exists for your “Lawful Universe”.

    Proofs for the irrationality of pi have been known for a long time. Where do you think that the idea that pi is irrational comes from? This is a truly bizarre example. I can only assume that you are limiting science to surveying or carpentry. All scientists include mathematics as a part of science, as much as we like to joke about the differences between mathematicians and physicists.

    The “marker for scientism” comment smacks of the ad hominem and is unworthy of you.

    The fact that a definition of the term scientism exits is not in dispute. What is in dispute is whether it is a valid concept and whether any serious examples can be given. You have given me more evidence that these examples do not exist. But, I am willing to be shown otherwise, which is why I am interested in how Briggs uses the term. Hey I admire Briggs, but I also like to put him on the spot.

  11. Ye Olde Statistician

    You did not establishing the existence of a lawful and empirical universe by means of natural science, but by means of circular and wishful thinking. Unless you can beat Descartes at his own game, how do you exclude “I made it up myself” in order to settle on “the universe is real”? Or is it simply an appeal to faith? (That is, to truth/trust.)

    Remember, this was not an assertion that the existence of a rational universe is not fact, it is in response to a request for examples of factual things that cannot be established by the methods of natural science. (We will leave aside the distinction between truth and fact.)

  12. William Sears

    A thought occurred to me. If the definition of scientism was expressed to mean: scientists sometimes claim to be able to understand things that no-one yet can understand you would be on firmer ground. Unfortunately the term is usually used to mean that certain areas of human experience must be declared off limits, and furthermore that these areas are fully understood by non-scientific or even mystical methods. This is my higher truth criticism. Also whereas the latter definition is the operative one, criticisms are met by recourse to the former. I have seen this time and time again.

  13. Ye Olde Statistician

    Empirical Universe: The fact that one must assume the ability to make observations before one makes them is an extremely weak criticism. But more importantly, this must be done by any approach whether scientific or not.

    Precisely. It is true, but not demonstrable by science. If “in the beginning God created” then it follows that there must be a creation. Further reflection can be found in two essays: “The Reality of the Universe” and “Cosmology: An Empirical Science?” in Stanley Jaki’s The Limits of a Limitless Science.

    Proofs for the irrationality of pi have been known for a long time.

    But the proofs are mathematical/logical/pure reason proofs, not empirical scientific proofs.

    All scientists include mathematics as a part of science

    As in the Darwin equations?

    The methods of mathematics and the criteria applied are different from those of the Physics. Natural science (the physics, i.e., the scientia of physical things) studies the metrical properties of physical bodies. It uses induction from the physical. Mathematics studies the properties of ideal bodies. It uses deduction from first principles. That the truths of mathematics can be applied to the physical world is what Einstein called a “miracle.” But that does not mean that the methods of physical science can be applied to mathematics. We don’t learn the truths of circles by measuring round objects. Aristotle and his successors defined the three great realms of knowledge as Physics, Mathematics, and Metaphysics, which represent three stages of abstraction from the empirical, and three kinds of knowledge: scientia, opinio, and fides. Cf. http://realphysics.blogspot.com/2006/10/degrees-of-abstraction.html

    The “marker for scientism” comment smacks of the ad hominem and is unworthy of you.

    Perhaps you do not understand what “ad hominem” means. But it has been true since the time of Hume and Descartes to dismiss the subjective properties of the universe as “not real” and this is most strong among those who worship science.

    What is in dispute is whether [scientism] is a valid concept

    Take it up with Karl Popper or Mary Midgley. I would not discount the sharpness of their minds when it comes to philosophical validity. Midgley offers any number of examples of scientism in her book previously noted.

    Biologist Austin Hughes notes that “All too many of my contemporaries in science have accepted without question the hype that suggests that an advanced degree in some area of natural science confers the ability to pontificate wisely on any and all subjects” and offers as an example “chemist Peter Atkins, who in his 1995 essay ‘Science as Truth’ asserts the ‘universal competence’ of science.”

    MIT physicist Ian Hutchinson claims, “Science, modeled on the natural sciences, is the only source of real knowledge.” And even way back when Henri de Saint-Simon proclaimed, “A scientist, my dear friends, is a man who foresees; it is because science provides the means to predict that it is useful, and the scientists are superior to all other men.”

    If the definition of scientism was expressed to mean: scientists sometimes claim to be able to understand things that no-one yet can understand you would be on firmer ground.

    But this would be wrong.

    Unfortunately the term is usually used to mean that certain areas of human experience must be declared off limits

    Nothing is “declared” to be “off limits.” Granted, the methods of natural science restrict it to the metrical properties of physical bodies, but this is a domain that stretches “from quarks to quasars.” So there are clearly things which natural science is incompetent to address. That’s not a declaration but a fact. Unless you think that Beethoven’s “Moonlight Sonata” is fully explained by the physics of vibrating strings.

  14. William Sears


    If I understand you correctly, you have postulated a very restricted definition of science and then have complained that these very limits prevent you from understanding the universe, while at the same time accusing anyone of scientism if they do not accept your definition. Incidentally your definition would exclude theoretical physics.

    What are Darwin equations and why are they relevant?

    Quote: “Perhaps you do not understand what “ad hominem” means.” I guess that you just can’t help yourself.

    Quote: “Unless you think that Beethoven’s “Moonlight Sonata” is fully explained by the physics of vibrating strings.” Sooner at later the conversation always degenerates to this. It reflects that the real objection to science is that it spoils the mystery. It is funny considering that Bach, at least, used a scientific approach to his music.

    I think that your last posting fits my previous complaint very well. That is the tendency to switch from the operative to the apologetic definitions of scientism in an extended argument. I am still waiting for serious examples, but I think that we have exhausted the discussion and I leave it to others, if any are reading this, to judge who has won the debate.

  15. Ye Olde Statistician

    Sears: If I understand you correctly, you have postulated a very restricted definition of science and then have complained that these very limits prevent you from understanding the universe

    They form no limits on my understanding. Restricting oneself to a single methodology might very well do so.

    accusing anyone of scientism, if they do not accept your definition.

    a) It’s not my definition. See Popper, Hayek, Feyerabend, Midgley, et al. for details. Incidently, I don’t think any of those folks were theists.
    b) I have accused no one of scientism, although I have quoted a few people held up by others.

    Incidentally your definition would exclude theoretical physics.

    I don’t see how. Erecting theories by induction from the empirical facts would seem the very business of science, if a bit metaphysical. Granted, some scientists have claimed that some of the theorizing has gone beyond the realm of the probative, Smolin on string theory, for example. But they are still talking about the metrical properties of physical bodies.

    What are Darwin equations and why are they relevant?

    One of the markers of the scientific revolution was the privileging of mathematics as the language of science. We have Newton’s equations, Maxwell’s equations, Mendel’s equations, and so forth. I’m sure Darwin’s equations must be in there somewhere.

    Quote: “Perhaps you do not understand what “ad hominem” means.” I guess that you just can’t help yourself.

    Sorry. A statement of fact is not an ad hominem unless it is a plea to either accept or discount an argument on the basis of some characteristic of the other person. It is not a mere corrective or observation. An essay on the issue is here: http://edwardfeser.blogspot.com/2013/04/what-is-ad-hominem-fallacy.html

    Quote: “Unless you think that Beethoven’s “Moonlight Sonata” is fully explained by the physics of vibrating strings.” Sooner at later the conversation always degenerates to this. It reflects that the real objection to science is that it spoils the mystery.

    What mystery? Just because a thing is not explicable by the scientific methods does not mean it is a mystery. Someone in the grips of scientism might think so, but I do not. It is much like a man who only allows the use of metal detectors as an instrument of discovery speaking of the “mystery” of wood.

  16. William Sears

    Ah, the Darwin equations comment was a joke. I should have seen that. I guess that I can not complain when people don’t get my jokes.

    Thanks for helping to sharpen my position on this topic and giving me insight on the uses and misuses of the term “scientism”. I think that I might continue to develop my speculation on the shifting definitions problem in the future. Maybe we can goad Briggs into giving us his view.

    Finally, civility does seem to be an acquired taste. I am still working on it myself.

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