Spinoza on Falsity

Contrary to most philosophy, which struggles to arrive at truth and yield access to true ideas, Spinoza’s epistemological conundrum is how to arrive at falsity and produce false ideas. Because his theory of knowledge is inextricably linked to his ontology, because modal ideas are God’s ideas (by 1P15), and because all God’s ideas are true (by 2P32), then all ideas – infinite, finite, divine, human and so on – are ostensibly true. Similarly, if, according to Spinoza’s parallelism, an extended idea accompanies every idea in thought, then it seems to follow that every idea has to agree with its object. The solution to this seeming paradox lies in Spinoza’s unique epistemological conception of falsity, as well as its relation to imagination, truth, adequacy and inadequacy.

To this end, the first part of what follows defines falsity by exploring its role in imagination and the first kind of knowledge. The second part distinguishes the external nature of falsity from the internality of inadequacy. The third part addresses and attempts to resolve possible objections to this characterization of falsity, including the argument that it leads to pure relativism, conflates subjectivity and objectivity, as well as Spinoza’s ostensible positing of false or inadequate ideas in God, which would undermine his metaphysical system. The final part considers the value of falsity, including its capacity to demystify superstition, refute skepticism and explain why we erroneously assume the possession of free will. Falsity also reveals the power and necessity of representation as volition, an active (never passive) conceiving of and by the mind that allows for the development of common notions.


Falsity and Imagination

Throughout the Ethics, Spinoza never defines truth. Truth is only given axiomatically, first in 1A6, which states, “A true idea must agree with its object,”[1] positing truth as an external relationship. This correspondence theory of truth and falsity is reinforced by 2P43S, which states, “[A] true idea has no more reality or perfection than a false one (since they are distinguished only through the extrinsic denomination).”[2] In other words, externality rather than content or nature distinguishes true ideas from false ones.

Truth and falsehood, however, do not have a strictly binary relationship.  The agreement of an idea with its object constitutes a sufficient and a necessary condition for the truth of an idea, but a failure to agree does not necessarily constitute falsity.  Spinoza writes:

If an architect conceives a building in proper fashion, although such a building has never existed nor is ever likely to exist, his thought is nevertheless a true thought, and the thought is the same whether the building exists or not. On the other hand, if someone says, for example, that Peter exists, while yet not knowing that Peter exists, that thought in respect to the speaker is false, or, if you prefer, not true, although Peter really exists. The statement ‘Peter exists’ is true only in respect of one who knows for certain that Peter exists. Hence it follows that there is something real in ideas through which the true are distinguished from the false.[3]

True ideas, in other words, must express the whole truth and require a placement within the finite causal nexus. An idea agrees with its object only if it also involves a representation of the relation between the object and the idea the infinite intellect has of it.  To be true, a modal idea and the infinite intellect’s idea must be the same. A true idea of a building or of Peter must correspond to an object and its complete structure of causality. False ideas, on the other hand, fail to agree and are mind-relative. Proclaiming Peter’s existence from a position of not knowing asserts a false idea whether or not Peter actually exists.

2P41 limits falsity to the effect of the first kind of knowledge,[4] imagination, which is a process of perceptually registering the traces of an object or event via a modification of the body or brain through memory, sensory experience, opinion and language. Perceptual experience is an amalgam of the external world and our own perceptual apparatus. That is, according to 2P16C, “the ideas which we have of external bodies indicate the condition of our own body more than the nature of the external bodies.”[5] Such ideas derive from indiscriminate encounters with things affecting our bodies. While Spinoza positions imagination below reason and intuition within his epistemological hierarchy, in Part II of the Ethics, he devotes the most attention to this first kind of knowledge.

Spinoza (re)develops the concept of falsity as a unique basis for his epistemology beginning with 2P33, which holds, “There is nothing positive in ideas on account of which they are called false.”[6]The subsequent demonstration argues reductio that falsity cannot exist in God. 2P35 provides the core of Spinoza’s concept of false ideas. He writes, “Falsity consists in the privation of knowledge which inadequate, or mutilated and confused, ideas involve.”[7]In its demonstration, Spinoza distinguishes this epistemological privation from absolute privation and ignorance. Because only minds have ideas, bodies cannot err, which precludes absolute privation. Yet to have a false idea is still to have some idea, which distinguishes falsity from absolute ignorance.

Spinoza exemplifies falsity through two examples, the illusion of free will (to which we will return) and the sun. He writes:

Similarly, when we look at the sun, we imagine it as about two hundred feet away from us, an error which does not consist simply in this imagining, but in the fact that while we imagine it in this way, we are ignorant of its true distance and of the cause of this imagining. For even if we later come to know that it is more than six hundred diameters of the earth away from us, we nevertheless imagine it as near. For we imagine the sun so near not because we do not know its true distance, but because an affection of our body involves the essence of the sun insofar as our body is affected by the sun (2P35S).[8]

To understand the sun as 200 feet away is to have a false idea, which is an image that represents a corporeal affection of an external body on ours. A person who has an idea of the sun unaccompanied by a working grasp of astronomy and optics understands only the contents of the sensory experience. To understand the sun as six diameters of the earth away is also to have a false idea, unless one also understands “the cause of this imaging,” which is to say, the complete causal network of which this image and its process of imaging are a part. Falsity derives from mutilation, understood as the fragmentation of an idea from its causal nexus, and confusion, understood as the conflation of one’s body with external bodies or the inability to distinguish one’s own body from other ones. Perhaps most significant, however, the imagination continues acting as it did even after falsity is revealed. Insofar as we experience and imagine, we err, as an inherent facet of being a finite mode interacting with the world.


Falsity and Inadequacy

The majority of Part II deals with the mind’s knowledge of external bodies, of its own body, and of itself. In all three cases, cognitive awareness occurs through experience and, as such is mostly – but not completely – inadequate. Inadequacy is phenomenologically distinct from falsity. The former involves the privation of the latter, but also includes some degree of certainty. An inadequate idea requires something not part of imagination, which falsity as privation cannot grasp. Contingent on happenstance and the common order of nature, falsity lacks this intrinsic mark of truth, so inadequacy is falsity without extrinsic referencing or correspondence. Unlike falsity, inadequacy is definitive and expresses (a lack of) coherence. 2D4 states, “By adequate idea I understand an idea which, insofar as it is considered in itself, without relation to an object, has all the properties, or intrinsic denominations of a true idea.” The subsequent explanation overtly distinguishes adequate ideas from true ideas (and inadequate ones from false ones). Spinoza writes, “I say intrinsic to exclude what is extrinsic, namely, the agreement of the idea with its object.”[9]

In 2P11C, Spinoza elaborates the contingent nature of falsity:

Therefore, when we say that the human mind perceives this or that, we are saying nothing but that God, not insofar as he is infinite, but insofar as he is explained through the nature of the human mind, or insofar as he constitutes the essence of the human mind, has this or that idea; and when we say that God has this or that idea, not only insofar as he constitutes the nature of the human mind, but insofar as he also has the idea of another thing together with the human mind, then we say that the human mind perceives the thing only partially, or inadequately.[10]

In other words, the ideas contained in the human mind are, along with the idea of human mind itself, also in God’s mind. Having an idea is not sufficient to have an adequate cognition of the object. Nor is God’s idea of the human mind enough for adequacy. God has adequate cognition through the idea of the human mind along with an additional idea or ideas. The human mind has an adequate idea only insofar as it too contains these additional ideas, which it often does not possess. This other idea (by 1A4) is the cause of an object or event. Spinoza asserts, “The knowledge of an effect depends on and involves the knowledge of its cause.”[11]

God’s idea of an object or event includes the idea within the human intellect, as well as the causal nexus of which it is a part. Inadequacy occurs in degrees, so humans can encompass some degree of adequacy, but never to the full extent of God’s intellect. The idea of the sun is adequate if it follows from other knowledge (astronomy, optics, neuroscience) and if the mind rather than external senses causes the idea. To be internally determined is to view the world through first causes rather than contingent features immediately evident to the senses. Internal consistency is to be without logical contradictions, to negate the need to refer to anything external to itself, and to reveal internal causes of which we also have adequate knowledge. On the other hand, to be determined externally is to be separated from these formal and material premises and to be enslaved by the common order of nature in which rationality is subordinated to the ostensible contingency of what seems to be fortuitous and arbitrary experiences.

So far we have seen that a true idea corresponds with its object and its complete network of causality. True ideas are positive qualities understood as activity and are also adequate – that is, in God’s mind. Falsity is also mind-relative but involves further complications. A false idea can either fail to correspond with its object, or it can correspond to an object but fail to correspond with its full causal network. Inadequate ideas, on the other hand, involve some truth but are uncertain, so they also entail some privation. Falsity then is exactly this privation – the mutilation and confusion – that constitutes a negative feature of inadequate ideas. All ideas, insofar as they exist in God are in fact true, but in the human mind, the same ideas can be understood as false.



Three obvious objections then emerge from Spinoza’s characterization of falsity and his example of the experience of the sun as 200 feet away, which seems to be absolutely, not relatively, false. First, Spinoza ostensibly posits false ideas in God. Second, he appears to promote a relativistic theory of knowledge in which all ideas are certain. Finally, he complicates the relationship between subjective modes and the objective infinite intellect. All of these objections can be considered through a further distinction between truth and adequacy or between falsity and inadequacy. Spinoza addresses the charge of relativism and distinguishes reliable certainty (truth) from unreliable certainty (falsity) through these concepts of adequacy and inadequacy.

The first objection can be explored through the demonstration for 2P32, which states, “For all ideas which are in God agree entirely with their objects (by P7C), and so (by IA6) they are all true.”[12] As a result, the idea of the sun as 200 feet away leads to the conclusion that either God has this false idea or that this idea is true, neither of which is satisfactory, However, if parallelism is understood as distinct from causalism and the stress in 2P7 is placed on the order and connection rather than objects and ideas, then one can argue that the order and connection of an internal structure operates parallel in thought and extension, but its perception by some modes might simply not understand this.

Another means of addressing this issue, also dependent on a distinction between truth and adequacy, as well as falsity and inadequacy, is to argue that God maintains adequate ideas of all objects and events even if some of those adequate ideas are of inadequate modal representations. Some of God’s ideas, that is, are reflexive. God understands the sun as 93 million miles away from the earth, but he also comprehends that the sun appears closer to a person located on Earth because of perspectival and optical illusions. Spinoza writes (in 2P30D), “So the knowledge of the duration of our body is quite inadequate in God, insofar as he is considered to constitute only the nature of the human mind, that is (by P11C), this knowledge is quite inadequate in our mind.”[13] Contingent relations, based on size, distance, properties of light and heat and the human nervous system are simply not commensurable with the infinite intellect. The existence of an extensional mode corresponding to my idea of the close sun is simply a state of my body, which is not false as much as inadequate in the infinite intellect.

Regarding the second point on relativism, Spinoza does argue (in 2P43), “He who has a true idea at the same time knows that he has a true idea, and cannot doubt the truth of the thing,” the scholium for which more succinctly contents that “truth is the standard both of itself and of the false.”[14] However, Spinoza is here closing the skeptical gap between certainty and truth. He is locating truth in immanent singularities rather than in transcendent universals. In this case, a true idea is self-evidently so to the individual having it, which precludes doubt. Truth serving as its own criterion is a valuable and strategic means for refuting any claim that truth and thought have to be verified through further recourse to an epistemic foundation. Truth is transparent, so if one understands the true nature of an idea, one has certainty regarding it. However, this does not extend to ordinary belief. One can believe something without it being true, or one can believe something now and something else later. Yet the principle of sufficient reason’s role in Spinoza’s epistemology assumes that falsity, if traced far enough, will eventually be discovered.

Finally, the third objection concerning the relationship between subjectivity and objectivity can be treated by the first kind of knowledge, according to which acts of understanding and judgment determine one’s scope of awareness and belong to a cognitive subject. Ideas do not exist independently of the act of thinking (hence Spinoza’s admonition in 2P43 against considering images as mute pictures). Ideas, that is, as acts of understanding and intelligibility constitute first-person awareness of some content. The acts of having and understanding ideas cannot be separated, and a subject cannot occupy multiple perspectives simultaneously. As a result, the infinite intellect must either contain an infinity of mutually exclusive subjective perspectives, or it must objectify them such that they no longer belong to this or that subject. The first option ostensible undermines substance monism, while the second option appears to break the relationship between finite and infinite intellects.

However, Spinoza’s positing of mind as the idea of our body serves to individuate minds and create subjectivity immanently. Within Spinoza’s metaphysical system, God is the adequate knowledge of our inadequate knowledge insofar as he absolutely knows all the ways he is known. He adequately knows himself in every way and from every perspective by which he is known. In fact, God’s knowledge forms the absolutely self-reflexive epistemological model we must try to express, experience, embody, intuit, and know if we are to come to have true and adequate knowledge. In short, Spinoza’s conception of falsity and the ostensible problems to which it gives rise can be resolved by comprehending falsity as an important part of the epistemologically self-reflexive system Spinoza facilitates to allow for the active conception of ideas, including our inadequate knowledge, in the exact way or from the very perspective from which the infinite intellect adequately knows them. God expresses himself in many ways, so all ways of knowing remain ways of knowing one substance rather than substantially different things.


The Value of Falsity

Imagination, imaging and image in themselves contain no falsity. The mind does not construct false ideas because it imagines but only because it lacks an idea that excludes the existence of things it imagines to be present. Imagination, as memory, language, sensory experience and the ideas derived from them, despite being the locus of falsity, is essential to life. False ideas have no form, yet, no less than true ones, they contain expressive content, are experiential, and allow us to familiarize ourselves with and relate to other bodies that in turn allow us to construct common notions. Falsity, that is, far from a total privation of knowledge, requires connection with others and necessitates encounters with a wide variety of other objects and events. We develop rational knowledge through experience and imagination.

2P49S, which states, “In the mind there is no volition, or affirmation and negation, except that which the idea involves insofar as it is an idea,”[15] reveals the target of Part II, namely skepticism and free will. Spinoza draws no distinction between the singular and the universal, the will and the intellect, volition and ideas. He removes the illegitimate binary separating thinking and knowing, assembling all knowledge (true or false) immanently from one substance. He continues (in 2P49S1):

Indeed, those who think that ideas consist in images which are formed in us from encounters with [NS: external] bodies, are convinced that those ideas of things [NS: which can make no trace in our brains, or] of which we can form no similar image [NS: in our brain] are not ideas, but only fictions which we feign from a free choice of the will. They look on ideas, therefore, as mute pictures on a panel, and preoccupied with this prejudice, do not see that an idea, insofar as it is an idea, involves an affirmation or negation.[16]

This skeptical concept of the image is akin to a hylomorphic model of thinking that limits creative activities to an imposition of active but non-representational form onto representational but inert matter.  For Spinoza, to the contrary, the representational act of thinking constitutes explanation, a placement in a network of causality, and a process of making intelligible. The degree of certainty an idea enjoys is a function of the clarity with which it represents things. In 2D3, Spinoza emphasizes the activity (never passivity) of thought and the active conception, rather than passive perception, of the mind, so all representation is volition, an active conceiving by the mind, a mental action, and a display of power.

Rather than separate representational thinking from its epistemic foundation, truth becomes (by 2P43S) its own standard. An idea is immanently certain by virtue of its representational features. There is no subsequent need to find the transcendent ground for certainty. Ideas are transparent to themselves, so we are capable of some degree of certainty and are not, as skepticism claims, completely divorced from knowledge of the world. Knowledge instead becomes a matter of self-awareness and -reflexivity, shifting perspective from abstractions and generalizations to singularities and specificities in order to actively conceive of reality from the perspective of its own true and indivisible eternity.

Falsity involves uncertainty, but not doubt. To conceive adequately the nature of the human will is to see that all of our volitions are, like all events in the mind, determined by antecedent causes and to see to some extent what those causes are. Spinoza’s philosophy is synthetic rather than analytic. Because generalities are confused, Spinoza begins with singularities that follow the order of nature, and he proceeds non-teleologically. Inadequate ideas often lead us to regard things not as necessary but as contingent, since, lacking a sufficient and coherent causal story for them, we simply do not see them as necessitated by causes (IIP44). Were we absolutely free our behavior would not be determined from outside us and there would be no way to explain the relations that hold between us and other finite things.



Spinoza, Baruch. Treatise on the Emendation of the Intellect. Translated by Samuel Shirley. Edited by Michael L. Morgan, Complete Works. Indianapolis: Hackett Publishing Company, Inc., 2002.

Spinoza, Benedict de. Ethics. Translated by Edwin Curley. Edited by Edwin Curley, A Spinoza Reader: The Ethics and Other Works. Princeton: Princeton University Press, 1994.


[1] Benedict de Spinoza, Ethics, ed. Edwin Curley, trans. Edwin Curley, A Spinoza Reader: The Ethics and Other Works (Princeton: Princeton University Press, 1994), 86.

[2] Ibid., 142.

[3] Baruch Spinoza, Treatise on the Emendation of the Intellect, ed. Michael L. Morgan, trans. Samuel Shirley, Complete Works (Indianapolis: Hackett Publishing Company, Inc., 2002), 19.

[4] Spinoza, Ethics: 141.

[5] Ibid., 129.

[6] Ibid., 137.

[7] Ibid.

[8] Ibid., 137-38.

[9] Ibid., 116.

[10] Ibid., 123.

[11] Ibid., 86.

[12] Ibid., 137.

[13] Ibid., 136.

[14] Ibid., 142.

[15] Ibid., 147.

[16] Ibid., 148.

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