In philosophy intentional states mean the directing of one’s thoughts towards some object or idea. The philosopher Fred Dretske investigated the claims of the late philosopher Roderick Chisholm who argued that intentional states could only be mental states. This claim was derived from the thesis of the nineteenth century philosopher Franz Brentano in his 1874 book Psychology from an Empirical Standpoint. This essay will explore the claims made by Chisholm and Dretske and ascertain the validity of their arguments as to whether the all the contents of the mind are physical or mental states.

A feature of mental states is their content. For example, when I see a cat, I am perceptually aware of that cat, or when I believe that it is going to rain, my belief represents a state of the weather. David Chalmers (ed. 2002, p. 473) states that a feature of mental states is defined as its intentionality and essentially it can be assessed for its accuracy. My perception of the cat may be precise or imprecise, my belief that it is going to rain may be accurate or inaccurate and my desire to be loved may be satisfied or unsatisfied. Brentano argued that intentional states were solely mental states and distinguished mental states from physical states because they are non-spatial and are objects of awareness but, Chalmers writes (2002) also claimed that they reveal intentional inexistence which means that ‘they contain an intentional object themselves, an object at which they are directed’. For example, the statement I am thinking about fire-breathing dragons simply means that my thoughts are directed toward such dragons, even though they do not physically exist. Brentano contends that this ‘intentional inexistence’ is exclusive to psychical phenomena and that no physical phenomena can be said to have it (Feldman & Feldman 2008).

Chisholm focused on the concept of this inexistence of the object of the mind, the figment of one’s imagination (Chalmers 2002, p.473). He also contended that it is possible for two different states to be directed towards the same object and only psychological phenomena had this object directedness (Chalmers 2002, p.473). Chisholm accounts for the intentionality of thoughts through language, semantics, and mental expectation. He asserts that all of these demonstrate psychological intentionality and cannot be explained in non-psychological, nonintentional terms (Chalmers 2002, p.474). For Chisholm intentionality cannot be naturalized because no such psychological fact can be identified with a physical fact. The use of intentional sentences for Chisholm means that all of our beliefs about psychological phenomena can be expressed through them whereas physical phenomena cannot (Feldman & Feldman 2008). For example, the sentence ‘Diogenes looked for an honest man’ is an intentional statement because it does not rely upon the veracity of there being an honest man or not, whereas ‘Diogenes lived in a tub’ is not an intentional sentence because it relies upon the existence of a tub. Chisholm also recognises that we sometimes use intentional sentences to express physical facts and that also statements of probability sentences that describe comparisons are problematic (Feldman &Feldman 2008). However, Chisholm states (1957, p.484) that intentional statements that are the most relevant are the ones that are based upon psychological attitudes such as wishing, desiring, hoping, believing, assuming, and also perceiving.


Dretske (1994, p.492) contends that to fully understand that mind, one must know how it works and that this must entail a naturalistic or physical understanding of the mind. Contrary to Chisholm’s assertion that intentionality cannot be naturalized or that psychological phenomena cannot be expressed through physical phenomena, Dretske argues (1994, p.492)  that intentional ‘ingredients’ are necessary for any understanding of an ‘intentional product’, just as copper wire is needed for building an amplifier because it conducts electricity. To establish his theory that intentionality is already naturalized, Dretsky (1994, p.493) uses the example of a compass, a physical artefact which he states has an intentional purpose that is not intrinsic to it but to its user.Talk of the use of a compass gives it an intensional context. Therefore, we have intentional phenomena (the compass) with an intensional context (its use or purpose) and that this intensionality is as much a part of the intentional phenomena as its original intentionality. For Dretske (1994, p.493), naturalized intentionality exists all throughout the natural or physical world in phenomena that expresses something else about natural conditions that indicate how the rest of the world works. Examples that he gives are dark clouds, tree rings, or smoke.


Dretske (1994, p.493) also contends that the construction of a thought also requires a property of misrepresentation otherwise we would not have a naturalistic understanding of what we think, or its content and meaning. However, intentional phenomena like the compass, although able to misrepresent the information it was designed to deliver, is reliant on us to be able to do it. We are the ones whose purposes and attitudes determine the success or failure of such physical phenomena. It is the derived power of such objects to misrepresent that Dretske (1994, p. 495) suggests is essential for his recipe of the mind because it acquires the ability to detach meaning from cause. Through his recipe for thought, Dretske is asserting a purely physicalist ontology of the mind. Unlike Chisholm, physicalist philosophers, such as Dretske, see that there is no ‘unbridgeable gulf between the mental and the physical’ (Jacob 2010) and that reality can be described in both physicalist and intentionalist terms.  Brentano’s thesis that ‘no physical phenomenon manifests intentionality’ is objectionable to the physicalist (Jacob 2010). When Dretsky naturalizes intentionality by ascribing it to non-mental things, he is trying to authorize physicalism’s assertion that nothing is purely mental. For Dretske (Jacob 2010), information exhibits some degree of intentionality and is able to show both the intentionality of beliefs as well as its derived intentionality of an utterance that can misrepresent such information.


With his assessment of intentional inexistence, Brentano (Byrne n.d.) was simply stating that there are things that exist solely within the mind, such as unicorns or fire-breathing dragons or even our concepts of nothing or infinity. Intentionality must also be plainly distinguished from intensionality because mental states are not intensional, only sentences are (Byrne n.d.). A sentence can be intentional yet be completely separate from intentionality and also sentences that report mental states need not be intensional (Byrne n.d.). For Dretske to maintain that intentionality can be physically or naturalistically reduced he distinguishes between original or intrinsic intentionality and derived intensionality.  Dretske also maintains a causal theory of intentionality such that mental states represent something, like tree rings represent something, and argues that the intentionality of mental states can be reduced to their evolutionary biological function. It is Chisholm who has allowed this alteration to Brentano’s thesis that intentional inexistence can be defined by language and signs, and it is this alternative explanation that allows the reducibility argument of Dretske to be applied to mental states. When Brentano claims that intentionality is sufficient and necessary for mental states, the sufficiency claim can be found false, especially in Chisholm’s broad redefinement, which includes non-mental entities such as sentences or signs. This claim can be amended to original intentionality is sufficient for mentality, thereby making the claim have some chance of validity (Byrne n.d.). With the claim that intentionality is necessary for mentality it can be countered with the claim that sensations are mental states that are non-intentional (Byrne n.d.). However, even Dretske asserts that bodily sensations are mental perceptions and therefore are intentional (Byrne n.d.).

Brentano’s thesis is simply that thoughts about thoughts are intentional mental states. They have no physical determining factor. If they had a physical determining factor they would not be a mental state because they would be derived from physical perceptions. When I am thinking about something that does not exist, it has no place in the physical world. Like shadows on the wall that make one believe that there is a monster, they are a particular feature of our imagination. One cannot ascribe the misrepresentation of the shadow to the shadow but to the subject’s mind. The thoughts about that monster are further intentional states, however the language that the subject speaks about the monster or the painting that the subject does of the monster are not. Like Dretske, we could redefine those extra states as intensional states with further potential for intentionality but we have may have missed the point of Brentano’s original thesis that Chisholm supported. Mental states can be differentiated and separated from physical states because of their ability to misrepresent and also to change the information given to them through bodily sensations. Mental states have the significant causal role of being able to significantly disrupt an organism’s ability to survive through irrational fears or desires. Anorexia nervosa (U.K. National Health Service) and other mental illnesses that have dire physical effects are examples of such intentional mental states.

Chisholm’s account of mental states is based upon linguistics and semantics. Dretske’s response to Chisholm’s account that intentionality is naturalized throughout the world by its intensional context is valid. However, Brentano’s thesis, especially his second claim that intrinsic intentionality is sufficient for mentality, is also valid through such examples of the physical effects of a purely mental cause in such diseases as anorexia nervosa. Therefore, Dretske’s response to Chisholm that all intentional states have a purely physical cause is invalid because it does not take into account such mental states that can be classified as intentional which have causal roles.




Brentano, F 1874, Psychology from an Empirical Standpoint, D. Terrell, A. Rancurello, and L. McAlister, trans.; L McAlister, ed. (Routledge, 1995)


Byrne, A, (n.d.) ‘Intentionality,’ in Philosophy of Science: An Encyclopedia, ed. J. Pfeifer and S. Sarkar (Routledge n.d.), viewed 5 April 2012


Chalmers, D J (ed.) 2002, Philosophy of Mind: Classical and Contemporary Readings, Oxford University Press, New York, pp.474-474


Chisholm, R, 1957, “Intentional Inexistence” in Philosophy of Mind: Classical and Contemporary Readings, D.J. Chalmers (ed.), Oxford University Press, New York, pp. 484-91, 2002


Dretske, F, 1994, “A Recipe for Thought” in Philosophy of Mind: Classical and Contemporary Reading, D.J. Chalmers (ed.), Oxford University Press, New York, pp. 491-99, 2002


Feldman, R & Feldman, F, 2008, ‘Roderick Chisholm’, Stanford Encyclopedia of Philosophy, viewed 3 April 2012,


Jacob, P, 2010, ‘Intentionality’, Stanford Encyclopedia of Philosophy,viewed 4 April 2012,


U.K. National Health Service, Anorexia Nervosa, viewed 8 April 2012,