The Content Fallacy in Thomas Aquinas: A Response to Robert Pasnau

Part I: Pasnau’s Objection

In “Thomas Aquinas and the Content Fallacy,” Robert Pasnau lays out a strong case that Thomas Aquinas is frequently guilty of a gross mistake in reasoning called “the content fallacy.” Pasnau carefully presents several examples throughout his essay, but they all boil down to the following syllogism:

-Aquinas argues from how a thing exists to what it is about.
-To argue from how a thing exists to what it is about is to commit the content fallacy.
-Therefore, Aquinas commits the content fallacy.

In what follows, I hope to show that Pasnau’s argument fails to prove that Aquinas is guilty of the content fallacy. In particular, Pasnau has overlooked crucial metaphysical principles that Aquinas takes for granted in the cases cited by Pasnau. Once one attends to these crucial principles, which Aquinas articulates and defends in other places, Pasnau’s objection evaporates.

To that end, the following treatment will come in two parts. In the first part, I will explain Pasnau’s account of the content fallacy and why he thinks it applies in the various texts he presents. This will help determine precisely where Pasnau’s disagreement with Aquinas lies. In the second part, I will argue that Thomas does not make unwarranted jumps from intrinsic characteristics of the mind to intentional aspects of thought, but that he delivers the kind of logical connection Pasnau demands in his treatment of universality in the third chapter of De Ente et Essentia. There Aquinas shows that universality follows necessarily from the formal likeness of a material substance existing in the mind by an immaterial mode. It follows from this

that the minor premise of the above syllogism is false, refuting Pasnau’s central case against Aquinas.

II. Pasnau’s Objection

On Pasnau’s account, the content fallacy is a defect in reasoning specific to objects with representational content (thoughts, imaginations, sensation, etc.) in which one fails to distinguish the object itself from the representational content. Hence the name, ‘content fallacy.’ Pasnau defines it in the following way:

‘The content fallacy’ is my name for the mistake in reasoning that comes from conflating two kinds of facts: facts about the content of our thoughts, and facts about what shape or form our thoughts take in our mind.1

Pasnau calls facts about the thoughts themselves and the “shape or form” they take in the mind ‘intrinsic qualities’ and facts about the representational content or object of thoughts ‘intentional qualities’. To illustrate, he provides an obvious example. Suppose “Bob is thinking about a red sports car.” “The red car” is an example of an intentional characteristic of thought. Clearly it does not follow from this that “Bob’s thoughts are red.” This would be a fact about the intrinsic quality of thought. To conclude one from the other is to commit the content fallacy. Because they are logically disconnected, “an argument in either direction may be an instance of the content fallacy.”2 Again, when I say, “that is a dirty thought,” I do not mean something about the intrinsic quality of the thought, i.e, that the thought itself is dirty. Rather, I mean something about the intentional qualities of the thought, i.e, that the contents of the thought do not accord with good morals. In general, then, the content fallacy arises when one confuses the object of thought with the thoughts themselves. This can lead one to mistakenly reason from intrinsic qualities to intentional qualities (or vice versa) without adequate justification and so is repugnant to sound reasoning.

According to Pasnau, this fallacy is generally quite common and in Aquinas’ work, it is “embarrassingly and damagingly widespread.”3 But despite its apparent prevalence, some scholars dispute Pasnau’s charge against Aquinas. Ed Feser, for example, briefly (though firmly) says in a 2013 paper that “[Aquinas] is committing no such fallacy…certainly there is a more charitable way to read [him].”4

Although he proposes an alternative interpretation, Feser’s rebuttal is relatively terse. Moreover, it is unclear whether or not he faithfully captures the substance of Aquinas’ argument or adequately considers the depth of Pasnau’s objection.

Another response to Pasnau is that of Gyula Klima, who offers an alternative interpretation of Aquinas that identifies a spatio-temporal representation of individuals within certain classes of cognition, particularly sense cognition. He argues that if a cognitive power is constrained to represent in the spatio-temporal mode, it will necessarily represent only particulars. And this is the case with the senses:

The senses represent singulars in their singularity because they necessarily represent the sensible features of material objects together with the material individuating conditions of these features, namely, the spatio-temporal dimensions determining the designated matter of these objects here and now.5

Klima argues that since the understanding is immaterial, it cannot represent by means of these spatio-temporal features. Through abstraction, he says, the intellect “has to strip the [representations of sensible objects] precisely of these material conditions.”6 While Klima concedes that this does not entail a logical necessity, it does entail a natural necessity which, “seems [to be] all that is needed address Robert Pasnaus’ concerns.”7 As with Feser, however, this brief response seems to leave room for a more thorough investigation into the details of Pasnau’s critique.

The core of Pasnau’s objection is that he does not see Aquinas offering adequate justification for why specific intentional characteristics follow from given intrinsic characteristics of given particular cognitions. Pasnau considers many texts to substantiate this fundamental claim throughout his article but the lion’s share of his analysis goes to a passage from Aquinas’ commentary on De Anima. It will be helpful to have the entire argument in Aquinas’ own words close at hand, and it goes as follows:

It must be noted about the first that while the sense-faculty is always the function of a bodily organ, intellect is an immaterial power—it is not the actuality of any bodily organ. Now everything received is received in the mode of the recipient. If then all knowledge implies that the thing known is somehow present in the knower (present by its similitude), the knower’s actuality as such being the actuality of the thing known, it follows that the sense-faculty receives a similitude of the thing sensed in a bodily and material way, whilst the intellect receives a similitude of the thing understood in an incorporeal and immaterial way. Now in material and corporeal beings the common nature derives its individuation from matter existing within specified dimensions, whereas the universal comes into being by abstraction from such matter and all the individuating material conditions. Clearly, then, a thing’s similitude as received in sensation represents the thing as an individual; as received, however, by the intellect it represents the thing in terms of a universal nature. That is why individuals are known by the senses, and universals (of which are the sciences) by the intellect.8

Pasnau proceeds to give a meticulous exegesis, commenting line by line. While there is much worthy of reflection in his treatment, for the present purpose it will be sufficient to highlight the critical points of Aquinas’ logical progression disputed by Pasnau.

The first hint of the content fallacy, according to Pasnau, is that Aquinas begins and ends at different levels of factual statement. The argument starts with, “the sense-faculty is always the function of a bodily organ [while] intellect is an immaterial power.” Here, Aquinas is taking up facts about how the powers exist in themselves, i.e., their intrinsic qualities. However, the concluding statement of the argument seems to be on the level of intentional qualities of the cognitive powers: “Individuals are known by the senses, and universals by the intellect.” Aquinas is asserting something about the objects of sensation and understanding. Consequently, unless Aquinas has some justification for this shift from intrinsic to intentional qualities, he must be committing the content fallacy.

Pasnau summarizes the first eight statements of Aquinas’ argument without significant challenge. That the senses are corporeal and the intellect is an immaterial power, Pasnau seems willing to grant. While he disputes the universality of the claim that “everything received is received in the mode of the recipient,” he does not think Aquinas’ argument fails here since all that is required is the more restricted principle that “everything received in something corporeal is received corporeally; everything received in something incorporeal is received incorporeally.” Pasnau finds this statement “entirely uncontroversial.”9

He also grants Aquinas’ general principles that common natures are individuated by “matter existing within specified dimensions,” and that “universals come into being by abstraction from such matter and all the individuating material conditions.” Most importantly, since Aquinas’ premises thus far pertain to the intrinsic qualities of cognition, there is no potential for the content fallacy.

The problem for Pasnau is that in the final lines of the argument Aquinas is concluding something about the content of cognitionwhich means he has entered the realm of intentional qualities. According to Pasnau, this is a move for which he has not presented sufficient justification: “Generally the argument gives us no reason to think that the likenesses received in the senses will represent things as singular.”10 The same is true regarding his conclusion about the content of the intellect, for this also is a fact about the intentional qualities of the cognition. In both cases, according to Pasnau, Aquinas draws from statements about the intrinsic qualities of the cognitive powers and concludes something about their intentional qualities. Without an appropriate middle term, something that will allow Aquinas to proceed from intrinsic to intention characteristics, this argument constitutes an invalid inference in the mode of the content fallacy. Pasnau proceeds with a barrage of texts from the Summa Contra Gentiles, the commentary on the De Anima, and the Summa Theologiae, all of which show Aquinas concluding from the corporeity of the sense organ that the sense powers cognize only particulars. Likewise, he lists two more texts11 in which Aquinas concludes that the intellect cognizes universals apparently from the mere fact that it is immaterial. In each case, Pasnau has the same concern,

In all five of these passages Aquinas uses facts about the intrinsic qualities of sensible or intelligible species to explain facts about those species’ intentional qualities. In none of them does he even hint at a middle premise that might justify the connection.12

This parallels the problem Pasnau had with the text from the commentary on the De Anima quoted at length above. The common line of dispute in these examples shows that Pasnau’s root concern is not simply that Aquinas moves from intrinsic to intentional qualities but that he does so without adequate justification. This insight helps us formulate the original rendition of Pasnau’s general critique with greater clarity:

-Aquinas argues from how a thing exists to what it is about without adequate justification.
-To argue from how a thing exists to what it is about without adequate justification is to commit the content fallacy.
-Therefore, Aquinas commits the content fallacy.

Now we see exactly where the disagreement lies. Pasnau’s critique really reduces to the lack of a middle term on the part of Aquinas’ argument.

Pasnau’s position that the content fallacy constitutes an invalid inference seems to be a reasonable one and so the major premise is not where I wish to direct my reply. It is the minor premise that I propose to question. If it can be shown that Aquinas does have a middle term in his arguments for universality in the intellect and particularity in the senses, then the first premise is false, refuting Pasnau’s objections. This is what I hope to accomplish in part II of this paper.

Image attribution: Carlo Crivelli, Public domain, via Wikimedia Commons


  1. Pasnau, R. (1998). “Aquinas and the Content Fallacy,” in The Modern Schoolman, Vol. 75, p. 293 ↩︎
  2. Pasnau, “Aquinas and the Content Fallacy,” p. 294. ↩︎
  3. Ibid., p. 294. ↩︎
  4. Feser, E., (2013), “Kripke, Ross, and the Immaterial Aspects of Thought,” in American Catholic Philosophical Quarterly, Vol. 87, No. 1, p. 19. ↩︎
  5. Klima, G., (2009), “Aquinas on the Materiality of the Human Soul and the Immateriality of the Human Intellect” in Philosophical Investigations, Vol. 32, No. 2, p. 175. ↩︎
  6. Klima, “Aquinas on the Materiality of the Human Soul,” p. 178. ↩︎
  7. Ibid., p. 178n18 ↩︎
  8. Aquinas, Commentary on the De Anima, Bk II, Lectio 12. ↩︎
  9. Pasnau, “Aquinas and the Content Fallacy,” p. 297. This is a curious remark given the fact that a little later on the same page he says that “It’s not completely clear what is meant by the phrases ‘corporeally receive’ and ‘incorporeally and immaterially receives.’ It may be that a crucial ambiguity rests here.” It would seem that clarity as to the meaning of a statement is a prerequisite to determining whether or not it is a controversial one and ambiguity excludes clarity. ↩︎
  10. Ibid., p. 299. ↩︎
  11. QDA q. 3 ad 7, ST Ia 85.1c ↩︎
  12. Pasnau, “Aquinas and the Content Fallacy,” p. 303. ↩︎

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