2644-0652 Journal of Modern Philosophy 2644-0652 Aperio Press 10.25894/jmp.2809 Research Locke on Knowledge and Judgement: The One/Two-Act Debate Revisited https://orcid.org/0009-0005-5381-8521 Li Daiwei daiweili1985@gmail.com 1 College of Philosophy and Social Sciences, Northwest Normal University, Lanzhou 730070, China 22 12 2025 2025 7 1 24 28 02 2025 03 06 2025 Copyright: © 2025 The Author(s) 2025 This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.

This paper reignites the debate over Locke’s one-act versus two-act account of knowledge and judgement, reassessing the recent inclination to discuss his theory within the justified true belief (JTB) framework of Anglo-American analytic epistemology. After clarifying the key issues, it defends the one-act account by critically engaging with recent scholarship, highlighting weaknesses in the arguments of one-act proponents against the two-act account, and offering new counterarguments against the latter. Ultimately, it argues that situating Locke’s broader view of knowledge within a post-Gettierian epistemological framework is an ill-suited approach.

 Locke Knowledge Judgement JTB One-Act/Two-Act Debate 1. Introduction

There is a widespread narrative in contemporary Anglo-American literature on the history of epistemology that, until Gettier’s seminal paper (1963), the concept of (propositional) knowledge—since Plato—was universally understood as justified true belief (JTB). This narrative has recently been challenged, convincingly, in my view, by scholars such as Antognazza (2015, 2020), Dutant (2015), and Le Morvan (2017, 2023). This shift in the scholarly narrative provides an opportunity to reexamine the interpretations of historical figures shadowed by this narrative, scrutinize their underlying assumptions, and consider how these assumptions influence our understanding of historical issues. If the traditional narrative has indeed exerted a misguided influence, we should not only revise it but also propose a more accurate alternative. In this regard, Locke’s theory of knowledge serves as a pertinent case study.1

Lex Newman (2007) argues that Locke’s view of knowledge can largely be reduced to the justified true belief (JTB) account.2 In his article ‘Locke on Knowledge’ (2007), Newman begins by outlining two key characteristics of Locke’s definition of knowledge—the perception of (dis-)agreement and its restriction to ideas—before addressing the question of how Locke’s official definition of knowledge relates to the JTB account.3 At first glance, Locke’s definition appears incompatible with JTB: as Newman notes, ‘the perception of agreement as wholly constitutive of knowledge’ (2007: 319) seems to have little connection to the JTB framework.

Newman divides the prima facie divergence between Locke’s definition of knowledge and the JTB account into verbal and substantive senses. The verbal difference concerns terminology and is of minor significance; it can be easily resolved by substituting Locke’s term ‘assent’ with ‘belief’. Under this substitution, knowledge as justified true assent neither alters the core of JTB nor seems alien to Locke’s framework. However, the substantive difference remains: as Newman notes, the doxastic state ‘is in no way constitutive of knowledge’ (2007: 320). Nevertheless, Newman argues that this difference lacks practical significance because ‘Locke holds that the mind always assents to what it knows’ (2007: 320–21). Thus, Locke’s broader definition of knowledge can still be mapped onto the JTB account. In a lengthy footnote, Newman (2007: 321n.14) further emphasizes that his conclusion relies on an assumption of the so-called ‘two-act theory’ regarding Locke’s view of judgement and propositions. It claims that Locke has a clear awareness of three distinct cognitive elements: (i) the justifying apprehension (the first act); (ii) the true proposition (the agreement or disagreement of ideas) as the object/content of act;4 (iii) the mind’s assent/dissent to that proposition (second act).

In what follows, I will primarily challenge the two-act interpretation and argue that, for Locke, apprehension/perceiving (the first act) is identical to knowing/assenting (the second act), and that the mental proposition is not an object prior to any act of assent or dissent. In this process, I will also clarify several foundational concepts in Lockean epistemology. Moreover, I will contend that, even if the two-act reading holds some plausibility, the fundamental divide between Locke’s conception of knowledge and the justified true belief (JTB) account remains irreconcilable.

 2. An Overview of the Debate

The debate over the one-act versus two-act theory centres on whether Locke conflates the process of constructing or entertaining a proposition with the act/state of holding a specific attitude toward that proposition. Geach, who first criticized this conflation, describes the confusion of an unasserted proposition with assertion as a ‘monstrous and unholy union’ (Geach 1962: 51), highlighting its serious implications for understanding conditionals and disjunctions.5 In response to Geach’s critique, one might defend Locke’s position in four ways:

Admit that Locke conflates the two acts and that Geach’s critique is valid, but argue that this conflation is largely due to the limitations of pre-Fregean logic, making Locke’s error excusable. This view is supported by Owen (2007: 415–16) and Hill (2008: 200–201).

Defend the one-act interpretation, arguing that there is no confusion or blame to be assigned. The one-act theory is neither a mistake nor does it lead to absurd consequences within Locke’s philosophical framework or that of his contemporaries. Marušić (2014) has recently provided a strong defence of this position, and Weinberg (2016: 56–57; 2021: 4n.8) and Powell (2018: 27) have endorsed her arguments.

Claim that Locke developed an embryonic account of propositional attitudes and should not be interpreted as making such an obvious error. This view is supported by Ott (2004: 34ff.), Newman (2007: 321), and Anstey (2021: 41ff.).

Concede that Locke must be interpreted as a two-act theorist, but argue that this does not require imposing a Fregean model on his work. Instead, Locke’s two-act theory is non-Fregean and does not aim to address the problem of propositional attitudes. Van der Schaar (2008) adopts this position.6

I will defend the second interpretation by critically engaging with the fourth. Given that the first group also endorses a one-act theory, many arguments advanced by Owen and Hill apply equally to the second position. Besides, I find considerable merit in van der Schaar’s non-Fregean approach to Locke’s epistemology and have drawn significant insights from her work on his concept of knowledge. Some puzzles related to the one-act thesis may be better clarified by adopting her model; apart from the part that supports the two-act theory, van der Schaar’s arguments are fully compatible with, or even better aligned with, the second position.

 3. One-Act Theory

Before proceeding, two preliminary remarks are necessary. First, much of the debate relies heavily on the connection between Locke’s theory of judgement and Arnauld and Nicole’s Logic or The Art of Thinking (1662/1996). While discussing Locke’s one/two-act theory in this context is insightful, I cannot explore the Port-Royalians’ views in detail here. Instead, I will assume—without arguing—that the Port-Royalians endorse the one-act theory7 and that their influence on Locke is significant.8

Second, I do not aim to provide a systematic analysis of the pros and cons of the one-act theory or to defend my support for it in full range. Marušić (2014) has already done excellent work in this area, and there is no need to repeat her arguments. My goal, therefore, is largely focused on identifying the weaknesses and misleading aspects of her argument and proposing a way to address the resulting perplexities.

We now begin with an examination of three central concepts in Locke’s epistemology.

3.1 Locke’s ‘Knowledge’

The first concept is knowledge. In Essay IV, Locke famously defines knowledge as ‘the perception of the connexion and agreement, or disagreement and repugnancy of any of our Ideas’9 (IV.i.2, 525). The term ‘perception’ is equivocal here; it can signify either the act of perceiving or the product of that act. Locke employs both meanings in the Essay. For instance, in one passage, he states: ‘The two great and principal Actions of the Mind… are these two: Perception, or Thinking, and Volition, or Willing’ (II.vi.2, 128). The OED defines this sense of perception as ‘the process of becoming aware or conscious of a thing or things in general’. Elsewhere, Locke writes that ‘perceptions are produced in us by exteriour Causes affecting our Senses’ (IV.xi.4, 632).10 Here, ‘perception’ refers to the mental product of perceiving. The relation between the two uses of ‘perception’ could be described as follows: perception-made (the second sense) results from the act of perceiving or perception as an act (the first sense).11

The question, then, is: in which sense of ‘perception’ does Locke use the term to define his concept of knowledge? A few chapters later, we find a clue. Locke divides knowledge into two kinds based on how the mind apprehends truth. The first is ‘actual Knowledge, which is the present view the Mind has of the Agreement, or Disagreement of any of its Ideas…’ (IV.i.8, 527). The second is habitual knowledge, which arises when we perceive the agreement or disagreement of ideas in the form of a proposition stored in memory: whenever we reflect on that proposition, we immediately embrace its truth (IV.i.8, 527–28). Notably, Locke defines habitual knowledge in terms of actual knowledge: habitual knowledge is essentially past actual knowledge stored in memory.12 For Locke, actual knowledge is, first and foremost, an occurrent act of perception—a mental occurrence. It is therefore reasonable to conclude that Locke defines knowledge primarily in terms of the act of perceiving: knowledge is the perceiving of the agreement or disagreement of our ideas.13

 3.2 Locke’s ‘Proposition’

The second controversial passage concerns Locke’s understanding of ‘proposition’. Locke’s notion of ‘proposition’ is closely related to his concept of truth. In ‘Of Truth in General’, he states that truth is ‘nothing but the joining or separating of Signs, as the Things signified by them, do agree or disagree one with another. The joining or separating of signs here meant is what by another name, we call Proposition’ (IV.v.2, 574).

If we set aside the preconceptions of the modern notion of ‘proposition’ (such as Fregean Gedanke or Russellian propositions), we can easily discern from Locke’s statement—‘The joining or separating of signs here meant is what by another name, we call Proposition’—that a proposition, for Locke, is surprisingly also a mental act, much like knowledge. A proposition, in this sense, is the mental act of joining or separating signs.14 The result, or product, of this act is also a proposition, which we may call ‘proposition-made’.15 But is this act the same as the ‘perceiving’ in Locke’s definition of knowledge? Let us explore this further.

In the following sections, Locke identifies two kinds of signs—ideas and words—and then distinguishes two types of propositions:

First, Mental, wherein the Ideas in our Understanding are without the use of Words, put together, or separated by the Mind, perceiving, or judging of their Agreement, or Disagreement. Secondly, Verbal Propositions, which are Words the signs of our Ideas put together or separated in affirmative or negative Sentences. (IV.v.5, 575–76)

This definition incorporates the earlier definition of knowledge as the perceiving of the agreement or disagreement of ideas. As Owen notes, the most natural reading of this context is that Locke has a single act in mind: ‘[I]n knowledge, there is no distinction between perceiving the agreement or disagreement of ideas, forming the proposition, and knowing it to be true’ (1999: 47). However, Owen (2007: 415) also acknowledges that the definition may be consistent with the two-act theory: joining and separating ideas (proposition formation) constitutes the first act, while perceiving or knowing the formed proposition represents a second-order act directed at the first.16 Nevertheless, a closer examination of the two definitions together—knowledge and mental proposition—reveals that the two-act reading is implausible. According to two-act theorists, the act of proposition formation precedes the act of perceiving it: we first combine or separate ideas to construct a mental proposition (the agreement or disagreement of ideas), and then we perceive it to attain knowledge. In this view, knowledge appears to presuppose the act of proposition formation. Yet Locke’s definition of knowledge does not include the act of combining or separating ideas as part of its process; rather, the order is reversed. The definition of a mental proposition incorporates the definition of knowledge. It would be unreasonable to claim that knowledge exists prior to the formation of propositions: how could we perceive something before it even comes into being?17 Thus, I maintain that the one-act interpretation offers the only plausible reading of these passages.

The following features of Locke’s ‘proposition’ are worth highlighting to facilitate subsequent discussion:

A verbal proposition takes a declarative form, such as ‘snow is white’ rather than a that-structure like: ‘that snow is white’.18

A verbal proposition is better understood as a sentence-token rather than a sentence-type.19

A mental proposition is more fundamental than a verbal proposition.20

 3.3 Locke’s ‘Judgement’

The final concept I will address is ‘judgement’, which Locke employs in a distinctive manner:

The Mind has two Faculties, conversant about Truth and Falshood. First, Knowledge, whereby it certainly perceives, and is undoubtedly satisfied of the Agreement or Disagreement of any Ideas. Secondly, Judgement, which is the putting Ideas together, or separating them from one another in the Mind, when their certain Agreement or Disagreement is not perceived, but presumed to be so. (IV.xiv.4, 653)

Locke introduces judgement to address the limitations of knowledge. While knowledge, as an infallible faculty, is always certain and clear, human beings are prone to error. Therefore, another faculty—judgement—is necessary to account for our fallibility. Knowledge involves the perception of the agreement or disagreement of ideas, ensuring certainty and truth. Judgement, by contrast, is an inferior form of cognition that lacks direct perception and instead presumes the agreement or disagreement of ideas, dealing with probability and the likelihood of truth. As van der Schaar (2008: 336) explains, ‘Knowledge is explained prior to judgement, because judgement is explained in analogy with knowledge. One simply has to substitute “to presume” for “to perceive”’. Consequently, knowledge and judgement are two distinct and mutually exclusive categories of cognitive faculties.

But can we first judge something to be true and then come to know it? Theoretically, yes. Unlike Plato, Locke does not maintain an absolute boundary between what can be known and what can be judged (or believed).21 The subject matter of knowledge and judgement is, in principle, the same: the agreement or disagreement of ideas. However, there is no indication in Locke’s work that judgement persists after we attain knowledge of something that we previously only presumed to be true. Judgement is replaced by knowledge but does not transform into it.22

 4. Judgement: Propositional Attitude or Judgement-Candidate?

Beyond the aforementioned sense of judgement, scholars frequently discuss another use of the term: a generic notion of ‘taking-to-be-true’ or ‘holding-to-be-true’. This sense of ‘judgement’ is consistent with its modern epistemological usage—judging or believing something to be true or false. It is this notion that I take issue with. In my view, the difficulty with Owen and Marušićs’ one-act interpretation stems from their problematic attribution of this concept to Locke as a propositional attitude.

Owen argues that, although Locke never explicitly uses the term ‘judgement’ to address this broader sense of judgement, he is indeed concerned with it. Marušić describes this broader use as a kind of doxastic attitude: ‘coming to believe’. Both scholars contend that Locke posits a generic attitude of taking-to-be-true that applies across cases of both knowledge and judgement.23 I do not deny their supposition that, through knowing or judging something, we are taking it to be true, nor do I deny that Lockean affirming or denying constitutes a mental act of taking-to-be-true. What I reject is the explanation of this ‘taking-to-be-true’ as a modern notion of doxastic or propositional attitude, which inevitably involves—whether implicitly or explicitly—a modern concept of proposition.24

What, then, is the serious problem with applying the post-Fregean model of propositional attitude while associating the one-act theory with Locke?25 If, as one-act theorists argue, every act of forming a proposition inherently involves believing its truth or falsehood, then there is no room for merely conceiving a proposition—such as understanding or considering it without adopting any attitude. It seems that Locke, like all of us, requires the ability ‘to consider, suppose, or entertain propositions prior to committing ourselves to their truth or falsity’ (Owen 2007: 416). Owen (2007: 416–17) attempts to resolve this issue by introducing the notion of degrees of probabilistic judgement: entertaining a proposition is positioned as a midpoint between full belief (assent) and disbelief (dissent). Marušić (2014: 272) follows this approach. However, van der Schaar’s objection is compelling: if presumption (judgement) ‘were the genus of all intellectual, epistemic attitudes toward a proposition, there would be no reason to exclude knowledge as a species of this genus’ (van der Schaar 2008: 339). Yet, for Locke, judgement is fundamentally distinct from knowledge and cannot serve as its genus. If this is the case, then, following van der Schaar, we should acknowledge that on some occasions Locke does seem to presuppose a neutral proposition prior to knowing and judging, and thus embrace a two-act theory.

However, I do not believe this view can be sustained. As we have seen earlier, the Lockean proposition is process/production-ambiguous, mind-dependent, event-like, and takes the full form of a declarative sentence. How can these characteristics be reconciled with the post-Fregean realist view of logic, which treats propositions as mind-independent, object-like entities expressed in the linguistic form of a that-clause? Van der Schaar accurately identifies the crux of this problem and proposes her traditional alternative to the modern concept of ‘proposition’. According to her, ‘proposition’ is ambiguous, potentially denoting three things: (1) the act of joining or separating mental ideas; (2) the result or product of this act; and (3) the judgement-candidate. While the first two are relatively clear, the third concept is crucial, as it leads van der Schaar to her two-act interpretation.

In brief, a judgement-candidate is an unasserted proposition—a linguistic meaning-entity that can be asserted but need not be. It takes the form of a declarative sentence with an indicative mood yet lacks assertive force. Unlike Frege’s Gedanke, which, as a Platonic abstract entity, exists beyond space and time and adopts a that-clause structure, a judgement-candidate differs primarily in its agent-relative correctness.26 For instance, while the truth of Goldbach’s conjecture, in a Platonic sense, is wholly independent of any cognitive agent, a judgement-candidate’s validity—though potentially pre-existing, as with the conjecture before Goldbach—remains tied to an agent capable of demonstrating it.27

Compared to the post-Fregean model, van der Schaar’s ‘troika’—judgment as act, candidate, and product— resonates more closely with Locke’s thought. First, both ‘proposition-made’ and ‘judgement-candidate’ take the linguistic form of declarative sentences. Second, they do not presuppose a fully mind-independent meaning-entity. Third, and relatedly, the ‘true’ in ‘taking-to-be-true’ does not signify an epistemically unconstrained property of such an entity; thus, there is little justification for imposing a post-Fregean propositional attitude framework on Locke. Yet this alone is insufficient: even a moderate meaning-entity like the judgement-candidate is not an essential presupposition for Locke’s account. In my estimation, van der Schaar errs in ascribing to Locke the notion of ‘judgement-candidate’—a quasi-Fregean Gedanke—and thereby concluding that he endorses a two-act theory of judgement.

I offer four grounds for this critique.

First, the ‘judgement-candidate’, conceived as an ontologically neutral meaning-entity, though an improvement over Gedanke, remains alien to Locke and the late-scholastic tradition he inherits. In late-scholastic logic and semantics, ‘proposition’ (propositio or enuntiatio) does not denote a sentence-level meaning-entity; rather, it is conventionally classified into three types—spoken, written, and mental28—where its signification is merely the aggregate of its categorematic terms’ meanings.29 Locke himself does not develop a semantic theory of propositional compositionality or signification.30 Given his discussion of mental propositions, which closely aligns with Ockhamist doctrine,31 it is implausible to assume he would accept an abstract entity like the ‘judgement-candidate’ as the signification of a mental proposition.32

Second, the textual evidence from the Essay provided by van der Schaar does not conclusively demonstrate that Locke adopts the concept of a ‘judgement-candidate’. The combination of proposition-as-act and proposition-made is sufficient for understanding Locke’s view. For example, in one passage discussing habitual knowledge, Locke states:

A Man is said to know any Proposition, which having been once laid before his Thoughts, he evidently perceived the Agreement, or Disagreement of the Ideas whereof it consists; and so lodg’d it in his Memory, that whenever that Proposition comes again to be reflected on, he, without doubt or hesitation, embraces the right side, assents to, and is certain of the Truth of it. (IV.i.8, 527–28)

This passage does not, as van der Schaar concludes, confirm the existence of a neutral judgement-candidate prior to knowledge and judgement.33 All Locke emphasizes here is that in habitual knowledge, the agreement or disagreement of ideas has already been perceived. Once you recall what you have perceived (proposition-made), you immediately affirm it again (perceiving). In this case, the subject matter before the mind is not a judgement-candidate but the product of a propositional act. This interpretation coheres with the term ‘habitual knowledge’: ‘habit’ refers to what people have regularly done—the completed act itself—rather than the object acted upon.34 Locke’s description of the second degree of habitual knowledge reaffirms this point:

[T]he three Angles of a Triangle are equal to two right ones, one, who has seen and clearly perceived the Demonstration of this Truth, knows it to be true, when that Demonstration is gone out of his Mind; so that at present it is not actually in view, and possibly cannot be recollected: But he knows it in a different way, from what he did before … He remembers, i.e. he knows (for remembrance is but the reviving of some past knowledge) that he was once certain of the truth of this Proposition, that the three Angles of a Triangle are equal to two right ones. (IV.i.8, 529; my italics)

When someone forms, perceives, or demonstrates a proposition such as ‘the three angles of a triangle are equal to two right ones’, they possess actual knowledge of it. Later, they may forget the proof or be unable to form or perceive it again, but they can still claim to know it by appealing to the memory-based certainty that they once performed that process—in other words, by appealing to the propositional act they once completed. For example, if asked why they still believe a geometric theorem learned in school, they might respond: ‘Although I forget how, I am still convinced of its truth because I remember proving it before’. It is the memory of the previous action that ensures their conviction; there seems to be no need to interpret ‘proposition’ in these contexts as a pre-existing, mind-independent entity.35 A judgement-candidate is thus a redundant assumption here.36 Therefore, I suggest that we remove the concept of a judgement-candidate from Locke’s framework: his proposition is always known or judged as identical to either the proposition-made (the product of a propositional act) or the act itself.

Third, without presupposing the concept of a judgement-candidate or the modern notion of proposition, would Locke be trapped in an unavoidable predicament? Not at all. I fully agree with Owen when he emphasizes that ‘it is a fundamental error’ for post-Russellians ‘who are immersed in propositional attitude psychology’ (Owen 2003: 17) to impose the distinction between forming and understanding a proposition and taking it to be true onto Locke. If my two objections against van der Schaar are valid, I propose that we go further and more radically reject the assumption of a post-Fregean (Russellian) proposition in interpreting Locke.

Let me first address Owen’s concern. Citing Locke’s statement—‘We have the Ideas of a Square, a Circle, and Equality; and yet, perhaps, shall never be able to find a Circle equal to a Square, and certainly know that it is so’ (IV.iii.6, 540) —Owen (2007: 416) argues that Locke was aware (or should have been aware) of the need to merely consider a proposition. Otherwise, we could not even ask the question, ‘Is a square equal to a circle?’ without first understanding its meaning.37

However, if we set aside the post-Fregean concept of proposition and consider a question-sentence, it becomes clear that, from Locke’s perspective, asking a question simply involves uttering an interrogative sentence with an interrogative mood. In other words, we use words to construct a question-sentence to inquire about the relationship between two ideas. For example, taking any two inherently distinct and unrelated ideas—such as ‘matter and thinking’—we can ask, ‘whether any mere material Being thinks, or no’ (IV.iii.6, 541). It is unnecessary, as Owen imagines, to posit a meaning-entity or sentence-type like ‘a square is equal to a circle’ existing prior to the mind, waiting to be grasped or perceived,38 and then, in a separate act, questioned, desired, believed, assented to, and so on.39

The process, rather, is as follows: through experience (observation or reflection), we acquire separate ideas (such as ‘square’ and ‘circle’), use various categorematic terms to signify them, and form sentences with corresponding moods (interrogative, imperative, indicative, conjunctive, etc.).40 Only sentences with an indicative mood qualify as candidates for Locke’s propositions and are connected to his notions of knowledge and judgement. Before these sentences are composed, the objects of thinking and understanding are limited to ideas.41 The notion of a proposition as a pre-existing meaning-entity, prior to the mind’s construction, is thus an illusory concept imposed on Locke by contemporary epistemologists.42 This also explains why scholars search in vain in Locke’s Essay for accounts of other propositional attitudes, such as hoping and desiring. The answer is that desire, joy, and hope are not propositional attitudes for Locke, as he lacks the modern (standard) concept of proposition and propositional attitude psychology.43 Instead, he discusses these concepts—fear, desire, joy, hope, and anger—together in ‘Of Modes of Pleasure and Pain’ (Essay II, xx), categorizing them as passions caused by ideas.44

Finally, van der Schaar consistently argues that her concept of a judgement-candidate reflects the traditional understanding of ‘proposition’ and has its roots in scholastic thought, particularly in Ockham’s philosophy. I find this connection inaccurate and misleading.

First, the inaccuracy: van der Schaar claims that Ockham (in Quodlibetal Questions, Quodlibet 5, Questio 6) distinguishes between propositio apprehensiva and propositio iudicativa—a proposition merely entertained and an asserted proposition.45 This reference is inaccurate. Ockham never uses the terms propositio apprehensiva/iudicativa in this passage.46 The title of the fifth Quodlibet, question 6, is: ‘utrum actus apprehendendi et actus iudicandi differant realiter (Is an act of apprehending really distinct from an act of judging?)’ (my italics). The focus here is on the distinction between propositional acts of apprehension and acts of judgement—or, in other words, between entertaining and judging a proposition. For Ockham, as echoed by Locke, a mental proposition is primarily treated as a mental act, not as an object or content of the act. Ockham identifies four types of acts: two apprehensions and two judgements (assents),47 none of which corresponds to van der Schaar’s description of a judgement-candidate as a ‘sentence type together with its meaning’ (van der Schaar 2015: 316). Moreover, Ockham’s robust nominalist ontology only admits individual substances and individual qualities, making it highly unlikely that he would accept such an abstract meaning-entity.48

Now, the misleading part. By distinguishing two kinds of apprehension and two kinds of assent, Ockham appears to endorse a two-act theory. It is reasonable to assume that the apprehensiva/iudicativa distinction is one of the philosophical commonplaces Locke shares with Ockham’s doctrine. However, the matter is more complex. To avoid delving into intricate issues, I will highlight two key points. On the one hand, the view that knowing or judging is identical to propositional formation or apprehension (the one-act theory) was not uncommon during the late-scholastic period.49 On the other hand, regarding this theme, Locke seems less likely to side with Ockham and Buridan than with Gregory of Rimini, another prominent medieval scholastic thinker. Gregory is generally regarded as a proponent of proposition-judgement identity theories and, on several issues, disagrees with his contemporaries, Ockham and Buridan.50

Locke’s affinity to Gregory also provides an opportunity to address a significant puzzle that scholars have long struggled with: the alleged absurdity of Locke’s one-act theory in explaining complex propositions such as conditionals and disjunctions. The charge of absurdity regarding conditionals can be summarized as follows: a conditional can be accepted as true even if its antecedent is not accepted as true. However, under the one-act interpretation, forming a conditional requires accepting both the antecedent and the consequent as true, since both are propositions. This would render the truth-functionality of conditionals impossible.

Scholastic thinkers were well aware of this problem. One of their responses is that the antecedent and consequent of a conditional, as the principal components of a hypothetical proposition, are not themselves propositions and therefore are neither true nor false.51 But what are they, then? To clarify this, we need to introduce a dichotomy between non-ultimate and ultimate mental language.52 I will borrow Nuchelmans’ words to illustrate: the former consists of ‘those mental terms and propositions that are natural likeness of spoken or written expressions’, and the latter ‘contains the concepts and thoughts which render the expressions of a particular language meaningful and are natural signs of things’ (Nuchelmans 1980: 16; my italics).

The first group of terms is non-ultimate in the sense that they cannot produce proper ‘thoughts corresponding to their expressions’. Instead, they only ‘form indirect mental images of the sounds and letters’, which fail to achieve ‘ultimate cognitive success’ (Nuchelmans 1980: 16). This is akin to an English speaker parroting German words or sentences, or someone speaking heatedly, using words or sentences without truly understanding them. The second group of terms is ultimate because they carry conventional meaning based on what they signify and are universally understood.

To put it succinctly (though perhaps not entirely accurately), non-ultimate terms/propositions function as signifié (sound-images), while ultimate terms/propositions function as signifiant (concepts).53 Returning to the conditional, its antecedent and consequent cannot properly be called propositions or are only propositions in the non-ultimate sense, as they are pure mental images of spoken or written words. For example, in the sentence ‘the tree is green’ as the antecedent of a conditional, we are not using ‘tree’ or ‘green’ to refer to any concept of an actual tree or green object but only to the concepts of the words ‘tree’ or ‘green’ themselves. Consequently, no proposition in the strict sense is formed, and no issue of assent or dissent arises. Locke himself never addresses conditionals, nor is there direct evidence that he was familiar with this view. However, in response to the alleged absurdity perceived by contemporary philosophers, I believe it makes far more historical and theoretical sense to interpret this issue within a scholastic framework rather than through the lens of twentieth-century theory.54 Thus, Locke, influenced by Gregory of Rimini via Smiglecius, could easily have adopted this position had he considered the issue.55

 5. Concluding Remarks

To summarize, I have argued that, for Locke, the act of knowledge and the propositional act are fundamentally the same (the one-act theory), while judgement, as an inferior form of knowledge, constitutes a categorically distinct act. I then addressed a significant difficulty with Owen (2007) and Marušićs’ (2014) one-act thesis: the impossibility of merely conceiving or inquiring into a proposition without affirming or denying it. Echoing van der Schaar (2008), I argued that their proposed solution to this problem is flawed. Furthermore, I agreed with van der Schaar’s view that Locke’s conception of the proposition does not permit us to resolve the predicament surrounding it by situating it within the contemporary psychological framework of propositional attitudes, given his lack of a post-Fregean understanding of the concept.

Nevertheless, I diverged from van der Schaar’s alternative traditional conception of the proposition as a ‘judgement-candidate’ and her resultant two-act interpretation of Locke, for four reasons:

A sentence-level meaning-entity is inconsistent with the philosophical context preceding and including Locke’s era.

There is no textual evidence in Locke’s writings to support this assumption.

The absence of a Fregean notion of proposition does not place Locke’s thought in a problematic or insurmountable predicament.

Van der Schaar’s attempt to link her concept of ‘judgement-candidates’ to the traditional use of ‘proposition’ in the Middle Ages is historically inaccurate and misleading.

Accordingly, I argue that the first step in engaging with the debate over a one-act or two-act theory of Locke is to entirely remove the modern notion of proposition from the discussion. In other words, we should avoid treating Locke’s mental proposition as a self-sustained meaning-entity existing independently of mental construction, and we must cease interpreting Locke’s definition of knowledge through the lens of assumptions embedded in the post-Fregean framework of propositional theory.56 Once this point is clarified, the concerns surrounding the one-act interpretation of Locke’s theory of knowledge and judgement can be partially alleviated. What remains is to identify a viable path to address the alleged absurdity of conditionals by drawing on resources from scholastic thought.

If my foregoing arguments hold, Newman’s presupposition of a two-act reading of Locke and his ensuing quasi-JTB claim become unsustainable. Moreover, as noted initially, even if we set aside this debate and allow for a possible two-act interpretation, Newman’s assertion that Locke broadly endorses the JTB account remains unsubstantiated. Locke’s conceptions of knowledge and proposition diverge fundamentally from the post-Gettier framework on three grounds:57 (1) in his formal definition, ‘knowledge’ primarily denotes a cognitive act, not a mental state; (2) truth does not constitute an essential element of Locke’s knowledge;58 (3) belief is absent from his definition of knowledge, and his ‘taking-to-be-true’ does not align with the contemporary epistemological notion of a generic dispositional attitude.59

In a nutshell, Locke’s epistemology defies neat placement within the standard pigeon-holes of the JTB narrative.

All references to Locke’s Essay Concerning Human Understanding are to the Nidditch edition (Locke 1975) and are given by book, chapter, section, and page number.

Newman’s (2007) view serves as the guiding thread for my discussion in this paper. Other scholars may implicitly assume one or more theses of the justified true belief (JTB) framework when comparing contemporary analyses of knowledge with Lockean epistemology. For instance, Wolterstorff (1996: 12ff.) assumes that Lockean knowledge is primarily propositional and a form of belief. Similarly, scholars such as Mattern (1978) and Rickless (2008) interpret propositional knowledge as a central component of Lockean epistemology, particularly when Locke writes that our knowledge ‘all consists in Propositions’ (II.xxxiii.19, 401). Recently, however, Anstey (2021) and Weinberg (2021) have challenged this orthodoxy by arguing that Locke’s conception of knowledge primarily addresses a type of non-propositional or pre-propositional knowledge, closer to Russellian knowledge by acquaintance rather than propositional knowledge.

Newman (2007: 319) (problematically, in my view) endorses the JTB narrative, tracing it back to Plato. Unsurprisingly then, he sees Locke as adhering to this ‘tradition’.

I do not address the distinction between propositions as content and as objects of mental acts/states here, though this does not imply that such a distinction is nonexistent. For a detailed discussion of this difference, see Künne (2003: 258ff.).

For details, see Ott (2004: 41–44) and Owen (2007: 410–14). It is worth noting that Geach (1962) does not specifically name Locke in his critique. Moreover, this problem is not unique to Locke; Geach argues that all pre-Fregean philosophers are, to varying degrees, guilty of this conflation. Among others, the Port-Royal logicians, Antoine Arnauld and Pierre Nicole, are frequently cited as representatives of this confusion.

Additionally, the views of Ayers (1991, I: 104ff.) and Jaffro (2018) can be roughly categorized as aligning with the first and fourth positions, respectively.

For a defence of this view, see Nuchelmans (1983: 76–77), Buroker (1993: 461–62), Marušić (2014), and van der Schaar (2008); however, Ott (2004: 45–46) and Jaffro (2018: 182) argue against it.

See Ott (2004, 37ff), Marušić (2014), and Jaffro (2018).

The concept of ‘idea’ is delicate. Locke describes it as ‘the Object of the Understanding when a Man thinks’ (I.i.8, 47). I take this at face value to mean that an idea is an immediate object of the mind, regardless of its ontological status. However, this interpretation is not uncontroversial; an ‘idea’ can also be regarded as a mental act. See Nuchelmans (1983: 141–43), Chappell (1994: 26ff.), and Newman (2007: 317).

OED, s.v. ‘perception,’ illustrates these senses with a citation from Locke. See the OED’s entry for ‘Perception’, senses I.1.a and I.5.a. (September 2025).

‘Perception-made’ comes from van der Schaar (2009: 2–3). She provides a parallel example to illustrate this distinction: the term ‘promise’ can refer either to the act of promising, the deed itself, or the product of that deed, namely, the ‘promise-made’. It is important to note that ‘perception-made’ should be distinguished from the content of perception. While ‘perception-made’ as a result of perceiving is determined (albeit perhaps not causally in a natural sense) by the act of perception, the content of perception normally denotes an abstract entity independent of any particular act. For further discussion, see van der Schaar (2006: 35–37). The first philosopher to explore this distinction in detail was Kazimierz Twardowski (inspired by Bolzano), particularly in his work Actions and Products (1912, in Polish; English translation, 1999). One anonymous referee posed two interesting questions: can the ‘promise-made’ be considered an abstract entity, and is this act/product distinction applicable to other traditional figures? My response to the former is that it can be (as in Twardowski and van der Schaar) but does not have to be an abstract entity (e.g., Moltmann’s view). As for the latter, the answer is yes—for instance, Kant’s ambiguous use of ‘judgement’ reflects a similar act/product duality. The implications of this ambiguity for the exegesis of traditional theories of knowledge will be addressed on another occasion.

Memory as a storehouse is merely a metaphor; see Rickless (2007: 60) and van der Schaar (2009: 9).

Robinson (1971: 17) and Ayers (1991, I: 96) offer a similar diagnosis. Van der Schaar (2009: 3) provides further evidence: for Locke, knowledge is also a faculty of the mind, which should be understood in terms of its action.

Van der Schaar (2008: 330) and Hill (2008: 191) both emphasize this point in the same year, with Hill (2008: 193) referring to mental propositions as ‘event-like entities’. However, I find that Landesman (1976: 26) had already noted Locke’s ambiguity between process and product. Regarding the opposing positions of Hill and van der Schaar in the debate over the one/two-act theory, the interpretation of propositions as particular acts alone does not resolve the issue.

Van der Schaar (2008: 330) also terms the second sense of proposition a ‘judgement-candidate’ (an unasserted proposition) judgement. This view is disputed below.

See also Newman (2007: 321) and Anstey (2021: 41).

Marušić raises a similar objection of circularity against Ott: ‘[It] is problematic to be committed to the view that one forms a proposition because one already has a propositional attitude toward the proposition to be formed’ (2014: 270). Some might counter this circularity by suggesting that, in Locke’s definition of knowledge, the ‘(dis)agreement of ideas’ as a formed proposition is already implicitly implied. My response is that this seems to provide stronger evidence in favour of a one-act, rather than a two-act, theory. This is because, for Locke, forming a proposition involves affirming or denying two ideas in a specific manner, which simultaneously entails the involuntary perception of their (dis)agreement (IV.xx.16, 717). Furthermore, as I will argue later, the notion of a proposition as a neutral, pre-existing meaning entity awaiting the mind’s engagement is itself a misinterpretation—a myth—in the broader interpretive tradition of Locke’s epistemology.

Van der Schaar (2008: 329). This was also a consensus in the late-scholastic period. See Nuchelmans (1980: 3 and passim), (1982: 197) and Ashworth (1974: 121).

Marušić (2014: 257). This view is also common in scholasticism. See Ashworth (1974: 52–55) and (1978: 83ff.). Nuchelmans points out that, although a sentence-token is routinely conceived as a truth-bearer, some medieval philosophers were aware of the distinction between sentence-token and sentence-type. See his (1973: 266) and (1982: 207ff.).

Marušić (2014: 257–58). For an excellent analysis of the reasons why a mental proposition has such priority, see Nuchelmans (1980: 16–26). Although he is discussing late scholasticism, I believe this superiority of the mental proposition is equally applicable to Locke. Panaccio (2003) and Ashworth (1980, 1981, and 1984: 57ff.) provide further evidence for this.

Locke’s concept of ‘judgement’ is nearly synonymous with ‘belief’, though this is not always the case. See Ayers (1991, I: 86n.13).

For example, Locke says: ‘herein lies the difference between Probability and Certainty, Faith and Knowledge, that in all the parts of Knowledge, there is intuition; each immediate Idea, each step has its visible and certain connexion; in belief not so. That which makes me believe, is something extraneous to the thing I believe; something not evidently joined on both sides to, and so not manifestly shewing the Agreement, or Disagreement of those Ideas, that are under consideration’ (IV.xv.3, 655). Knowledge, therefore, is confined to a relatively narrow domain where the mind has direct access or evidence. If one has an intuition of the agreement or disagreement of ideas, they possess knowledge; otherwise, they are left with judgement. There is no intermediate state between the two. For further discussion, see Ayers (1991, I: 125ff.).

Owen (2007: 408); Marušić (2014: 256n.3, 260). Owen does not explicitly state that this broader sense of ‘judgement’ aligns with the modern concept of a propositional attitude, namely ‘belief’. However, I believe this is implied by his attempt to interpret Descartes’ view through the post-Fregean distinction between grasping the content of a proposition and judging it.

Marušić appears aware of the potential for confusion here. She cautiously opts for ‘doxastic attitude’ to describe Locke’s view, reserving ‘propositional attitude’ for discussing the perspectives of others, such as Ott, likely because the latter term presupposes a mind-independent, non-linguistic entity as its object or content—a notion incompatible with her interpretation of Lockean ‘proposition’. However, if we examine the origins of ‘doxastic attitude’ in the epistemological literature, we find that it is, broadly speaking, a subset of ‘propositional attitude’. The term ‘doxastic attitude’ was first introduced by Goldman (1978a: 515; 1978b: 525) to describe a generic form of propositional attitude, such as ‘belief’ or ‘disbelief’. Later, with the inclusion of ‘withholding belief’ (or ‘suspending judgement’), it came to denote a class of propositional attitudes—‘belief, disbelief, and withholding’—which Turri (2012: 355) refers to as the ‘Triad’. Thus, Marušić’s caution with terminology does not help her avoid the modern conception of the ‘proposition’ underlying propositional attitudes.

I use ‘judgement’ in Locke’s restrictive sense, ‘taking-to-be-true’, in the broader sense of judgement here.

By the standard ‘post-Fregean model’, I mean the view that ‘belief’ or ‘judgement’, as a generic taking-to-be-true (Fürwahrhalten), constitutes a propositional attitude an intellectual agent adopts toward a proposition. Here, a proposition is an abstract entity, external to and independent of the cognitive agent, typically expressed in the linguistic form of a that-clause. It serves at least three roles: as a truth-bearer, as the object of a psychological state, and as the meaning of a sentence. I treat the last of these as equivalent to the content of what is said, though, as Engel (1991: 16) suggests, a distinction between them is warranted.

‘Judgement candidate may be understood as relatively independent of the declarative sentence, but it may also be understood as a declarative sentence type together with its meaning’ (van der Schaar 2015: 316). For further clarification, see van der Schaar (2007: 65ff. and 2015: 314ff.)

This example is drawn from van der Schaar (2015: 316). I suggest that the entire framework is grounded in intuitionistic principles within the philosophy of mathematics and logic.

For more, see Nuchelmans (1980: 9ff.).

For instance, in the sentence ‘A tree is green’, ‘tree’ and ‘green’ function as categorematic terms, while the remaining syncategorematic terms facilitate its composition. This verbal proposition does not signify a state of affairs or a fact, such as ‘A tree is green’ as a whole; rather, it denotes merely ‘tree’ and ‘green’—encompassing all trees and all green things. Spade (2002: 166) terms this the ‘Additive Principle’, attributing it primarily to Ockham and Buridan.

‘Signification’ (significatio), a foundational semantic concept in medieval philosophy, cannot be straightforwardly assimilated into the modern philosophical vocabulary of ‘meaning’. See Spade (1988: 188ff.; 2002: 63ff.) and Ashworth (1974: 47ff.; 1977: 59ff.; 2010: 150ff.; 2015: 160–63). Nevertheless, for those seeking a scholastic antecedent to the modern concept of propositional meaning, the medieval doctrine of signification offers an unparalleled resource. See Kretzmann (1970: 771ff.).

Most analyses of Locke’s semantic theories centre on his thesis that words signify ideas (see Kretzmann 1968; Ashworth 1981, 1984). Panaccio (2003: 45ff.) argues that Locke lacks a theory of reference for spoken words and mental ideas, leaving him without a clear account of the unity of mental propositions—a view corroborated by Ashworth (1984: 60). Lenz (2010: 327n.196) challenges Panaccio, asserting that Locke posits a semantic principle for the composition of mental propositions, though he does not address their signification. However, a theory of signification—whether of ideas or propositions—does not equate to a modern meaning theory, at least not in Dummett’s sense. Thus, although Locke, in keeping with the scholastic tradition, provides a doctrine of propositional signification, it is untenable to assume that he develops a sentence-level theory of meaning. Ashworth (1984: 53ff.) contends that Locke lacks a modern meaning theory for words. For a broader discussion of why seventeenth-century philosophers did not develop a modern (Fregean) theory of meaning, see Hacking (1975, Part A).

For instance, they agree on the following points: (i) ideas are the basic components of mental propositions; (ii) a nominalist view of universals; and (iii) the priority of mental propositions over verbal propositions. On this, see Panaccio (2003, 39–42). Ashworth (2015, 156–76) further argues that Locke, in many respects, is closer to Buridan than to Ockham.

One might draw on Locke’s theoretical affinity to Gregory of Rimini (see below) to propose the concept of complexe significabilia as the signification of a mental proposition. Complexe significabile is the closest medieval and post-medieval notion to the modern concept of proposition, seemingly capable of fulfilling that role (cf. Gaskin 2008: 11–12). However, Ashworth frequently cautions against associating the medieval or post-medieval nominalistic term propositio with a proposition as an abstract meaning-entity that serves as the object of an intentional act, even under the guise of complexe significabilia (cf. Ashworth, 1977: 59; 1978: 83ff.; 1981: 68ff.). Recent work on complexe significabilia by Mandrella (2016: 200–212) argues that, for Gregory, complexly signifiables are intra-mental rather than extra-mental entities.

Van der Schaar (2008: 330) reads both senses of ‘proposition’ here as judgement-candidate.

Moltmann’s (2019: 191) recent remarks shed light on why the modern concept of ‘proposition’ is difficult to integrate into the causal chain of mental events: ‘Propositions as abstract objects cannot play causal roles, making content-based causation a puzzling phenomenon. Mental attitudinal objects, on the other hand, serve as the targets of content-related memory. We remember thoughts, beliefs, decisions, and intentions, rather than propositions. We may recall acts of thinking or deliberating without remembering their content, which would not constitute content-related remembering’. Her concept of ‘attitudinal objects’ largely aligns with the notion of ‘proposition-made’ here.

Another example: the second degree of habitual knowledge ‘is of such Truths, whereof the Mind having been convinced, it retains the Memory of the Conviction, without the Proofs. Thus a Man that remembers certainly, that he once perceived the Demonstration, that the three Angles of a Triangle are equal to two right ones, is certain that he knows it, because he cannot doubt of the truth of it. In his adherence to a Truth, where the Demonstration, by which it was at first known, is forgot, though a Man may be thought rather to believe his Memory, than really to know, and this way of entertaining a Truth seem’d formerly to me like something between Opinion and Knowledge, a sort of Assurance which exceeds bare Belief, for that relies on the Testimony of another’ (IV.i.9, 528; my italics). Here, Locke compares habitual knowledge with judgement based on testimony. Both rely on belief—in oneself or in others—rather than on direct perception. Specifically, habitual knowledge depends on memory-based, introspective states, whereas bare belief relies on the testimony of others. In other words, the basis for taking a proposition to be true in habitual knowledge is an internal psychological act or state, rather than an external object or state of affairs. Kant expresses a similar idea when he discusses the ‘objective sufficient ground’ for Wissen; see Chignell (2007: 41) for further discussion.

In other texts cited by van der Schaar (IV.xviii.2, 689; IV.xx.15, 716), the term ‘proposition’ can also be interpreted as referring to a propositional act or proposition-made.

Marušić (2014: 271) poses two similar problems: the problem of mere conception and the problem of inquiry.

As Hill (2008: 191) precisely states: ‘whatever a [Lockean] mental propositions is, it ought not be an “Object of the Understanding”. Mental propositions ought not be the sort of thing that the mind acts upon, not the sort of thing that the mind takes in as content or accepts as presented to it’.

Frege famously articulates this view in ‘The Thought’ (1956: 294): ‘An interrogative sentence and an indicative one contain the same thought; but the assertoric sentence contains something else as well, namely assertion. The interrogative sentence contains something more too, namely a request’. For critical perspectives on this point, see Künne (2010: 423–29) and Hanks (2007).

This was the standard semantic order at that time: the meaningfulness of individual concepts or terms is always prior to or more basic than the meaningfulness of judgement/sentence. It is Kant who first reverses this trend (cf. Brandom 1994: 160ff.).

Hill again (2008: 191): ‘Mental propositions ought to be understood as some sort of special mental act, the results of the mind’s thinking or reflection on two ideas’. Alternatively, in my terminology, the Lockean mental proposition is ambiguous, referring either to a propositional mental act or to the proposition-made.

Peter Hanks’ recent account of the modern concept of proposition is consistent with the view I present here (though he does not reference any historical figures). Hanks rejects the Fregean distinction between force and content, arguing instead that propositional content is a force-laden entity of act-type: ‘Fregean entertainment is supposed to be a kind of neutral cognitive contact between a person and a proposition, which serves as necessary precursor to, or ingredient in, judgement and assertion. This is an illusion bred of unquestioning acceptance of the Fregean picture. In most cases, when we make a judgement, we just predicate a property of something. There does not have to be any bare contemplation of a proposition prior to this act of predication, and there is no compelling reason to think that somehow contained inside the act of predication there is something neutral and non-committal’ (2015: 10).

When I speak of ‘standard’ accounts, I do so in contrast to what I consider ‘non-standard’ approaches, which construe propositions as types of mental acts or as the products of such acts in the mind. Act-based propositional attitude reports have been developed by Soames (2010) and Hanks (2015), while product-based reports are found in Moltmann (2013, 2017). I sense that these contemporary non-standard approaches to understanding propositions bear greater similarity to traditional views than to the Fregean model. This also reinforces my conviction that contemporary standard propositional attitude reports should not be hastily assumed, without question, to be a universal and uniform model applicable to every traditional philosopher, particularly those who predate Bolzano. Locke is a prime example, as is Kant.

For more, see Marušić (2014: 273).

Van der Schaar (2007: 68): ‘If the “proposition” is asserted, it is called propositio iudicativa; if it is merely entertained, it is called propositio apprehensiva (Ockham, Quodlibetal Questions, Quodlibet 5, Questio 6; the distinction was common knowledge; see Nuchelmans, 1980, p. 27, 89). Irrespective of whether an assertion is made, the assertion-candidate, the enuntiabile, is that which is assertible (Nuchelmans, 1973, p. 169)’. See also van der Schaar (2008: 329n.2; 2015: 304–5).

I doubt that these terms could be found in Ockham’s other works. The terms actus/notitia apprehensiva (apprehensive act) and actus/notitia iudicativa (judicative act) are more commonly used in medieval scholarship. For further discussion, see the entry ‘Urteil’ in the Historisches Wörterbuch der Philosophie (1971-2007), particularly the section on Ockham. In the Quodlibetal Questions, Ockham uses ‘actus’, but he employs ‘actus’ and ‘notitia’ interchangeably, as noted by Schierbaum (2014: 176). In Nuchelmans (1980), which van der Schaar cites, the terms propositio apprehensiva/iudicativa appear on page 27 without textual references. On pages 74–75, Nuchelmans uses the English terms ‘apprehensive/judicative proposition’ and refers to the same Ockham text I have cited here, but the Latin terms he provides are notitia apprehensiva and notitia iudicativa. However, the Latin terms provided by Nuchelmans are not entirely accurate, as Ockham only uses ‘actus’ in Quodlibet V, q. 6.

In short, the two apprehensions are, respectively, forming a mental proposition and reflecting on that act of formation. The two judgements or assents are their counterparts: taking something to be the case and affirming that it is true. See Nuchelmans (1980: 74–75), Panaccio (2004: 31–36), and Schierbaum (2014: 174ff.).

See Spade (2002: 165ff.).

See Nuchelmans (1980: 93).

For the comparison see Nuchelmans (1973: 195–202, 227–237, 243–250); for Gregory and Buridan in particular, Klima (2008: 203–209). The exploration of Locke’s scholastic background can be found in Ashworth (1980: 59–68; 1984: 55–65; 2015: 156–75; 2016: 82–99) and Lenz (2010: 111ff.). Locke’s endorsement of Gregory’s view may have been influenced by the Polish logician Martinus Smiglecius, whose widely used textbook Logica (1618) circulated at Oxford during that period. See Ashworth (1981; 1984: 55–65) and Lenz (2010: 25, 120ff., 283–88).

This does not amount to denying that ‘if…then’ is a truth-functional connective. A more complete picture of compound propositions in the medieval period is provided by Nuchelmans (1980: 78–85, 94–102) and Ashworth (1974: 147–66).

Or, in other terms, mental language improperly versus properly so-called. Gregory proposes this distinction, drawing on Augustine and Anselm (cf. Spade, 1980: 104n.136, 115n.279). This distinction gained wide acceptance among late-medieval logicians (cf. Ashworth, 1974: 44–45; 1981: 62).

Further discussion of this distinction can be found in Spade (1980: 19–21, 28–29), Meier-Oeser (1997: 158–62), and Lenz (2010: 127ff.)

In this regard, I remain sceptical of attempts to apply contemporary models to circumvent the same absurdity in Locke’s framework, such as Ott’s Fregean truth-functional analysis (2004: 41–49) or Hill’s Ramseyian ‘suppositional theory’ (2008: 201–2).

Marušić (2014: 275–76) suggests that a complex proposition incorporates the idea of a proposition rather than the proposition itself as its component, an insight that closely aligns with the position I advance here. However, she does not connect this to its scholastic antecedents. Powell (2023) has recently extended her analysis further.

Ayers (1991, I: 315n.84) offers a similar conjecture. A detailed and comprehensive exploration of how this notion applies to Locke’s framework is provided by Lenz (2010: 127–48, 326–29), with particular attention to conditionals (338–39).

Marušić (2014: 257) is correct in asserting that ‘Lockean mental propositions are formed by the mind, through a mental act’. However, she unfortunately does not fully relinquish the standard Fregean framework, which limits her interpretation of Locke’s theory.

All three points were first advanced by van der Schaar (2009: 10ff.); for further details, see her article. I will not elaborate on them here.

This point warrants clarification. For Locke, knowledge is infallible—falsehoods cannot be known—yet it is not defined by a proposition’s truth-property. Rather, knowing, or perceiving, constitutes a primitive notion, capable of elucidating other concepts but not reducible to them. Put differently, a perception’s truth as knowledge stems not from conveying the correctness of its object or meeting an external justificatory truth-condition, but from its inherent status as a ‘true’ perception. In essence, truth emerges as a product of the perceptual act, not as its antecedent.

Locke frequently employs the term ‘belief’, alongside ‘assent’ and ‘opinion’, to denote a specific outcome of probable reasoning that falls short of knowledge (V.i.2, 525; V.xv.3, 655; IV.xv.9, 663). This usage is more closely associated with religious belief or faith (‘belief in’) rather than with the modern epistemological notion of belief (‘believe that’). Moreover, Locke never suggests that belief (or assent) could function as a genus of knowledge. Newman (2007: 320) acknowledges this but, based on his two-act theory—where knowledge as the perception of agreement or disagreement between ideas is a distinct act or state from the generic act of taking-to-be-true—he argues (2007: 320n.12) that the one-act interpretation, which equates assent (taking-to-be-true) with perception, might make Locke’s conception of knowledge more compatible with the JTB tradition. However, one-act interpreters need not bite this bullet, as Locke primarily uses ‘assent’ to refer to a judgement expressed in words. In other words, judgement is a probabilistic mental proposition, and assent is its corresponding probabilistic verbal proposition (IV.xiv.3, 653). While Locke occasionally retains the generic use of ‘assent’ in the first book of the Essay (I.ii.5; I.ii.8; I.ii.12), this does not equate it with a propositional attitude. As Owen (2003: 17) observes, ‘assent is not an attitude one takes towards a proposition already formed. So, when Locke speaks of a self-evident proposition as something one ‘assents to at first sight’ (IV.vii.2), he is not saying that we believe or assent to something known; he is just saying we come to know it. For further discussion of Locke’s concept of ‘assent’, see Marušić (2014: 261–62) and van der Schaar (2009: 11).

 Acknowledgements

This work was supported by the Center of Modern Thought, College of Social Sciences, Yangzhou University, Yangzhou, China.

 Competing Interests

The author has no competing interests to declare.

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