One insight of evolutionary biology is that every cell and organ in our body is adapted to its local environment for the purpose of making it more likely that our genes will survive into the next generation. Consequently, it’s helpful to think about the brain’s role in propagating our genes. Our brains facilitate our survival and promote our ability to find a partner and reproduce by using thought, calculation, prediction, and inference. For this reason, our natural and genetically primed ways of thinking do not necessarily serve the goals of philosophy, science, or truth. Figure 2.2 The “mind-brain” problem points to the unclear relationship between our thoughts, feelings, and perceptions, and the neurological and electrochemical interactions that take place in the brain. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license) Philosophical Caveats about “Brain Talk” Before we get much further, note that it is important to be cautious when we talk about brains and minds, which are distinct concepts. In fact, the relationship between mind and brain is one of the central problems of metaphysics, known as the “mind-body problem,” which might just as well be called the “mind-brain problem.” Briefly stated, the mind-body problem is the problem of understanding the relationship between the organic gray and white matter in our skulls (the brain) and the range of conscious awareness (the mind). We know that the brain and central nervous system provide the physical basis for our thoughts, perceptions, emotions, imagination, and desire—in short, our entire mental life. But biology does not tell us what the relationship is between our private mental life and the neurological, electrochemical interactions that take place in the brain. Is the relationship of the mind to the brain like the relationship between lightning and electrical discharge or a rainbow and the refraction of light through water droplets? In other words, is “the mind” just the term we use to label certain kinds of brain activity? Some philosophers think so. However, mental activity is not easily associated with any specific brain activity. Additionally, there seems to be something about the subjective experience of our mental life that is lost when we attempt to explain it fully in terms of brain activity. So other philosophers maintain that the mind is something different from the brain. Nonetheless, the mind and the brain are closely and somewhat mysteriously connected. As a result, it can be helpful to use the resources of psychology and cognitive science (the study of the brain’s processes) to help us understand how to become better thinkers. We can think of the resources from psychology and cognitive science as providing us with a description of how the brain actually behaves. By contrast, when we study critical thinking, we are interested in how we ought to think. Being aware of how we do think may help us devise effective strategies for how we ought to think, but we should understand that the descriptions provided by psychology are not determinative. In this chapter, we explore psychological findings that can help you become more reflective about the ways your thinking can go wrong. Connections Read more about the nature of the mind and the mind-body problem in the chapter on metaphysics. Representation as Projection While you may consider thinking to be made up of ideas or thoughts, philosophers and cognitive scientists use the term representation to describe the basic elements of thinking. Representations are information-bearing units of thought. This notion of representation can be traced back to Aristotle and has played a significant role in the history of philosophy, but in contemporary philosophy the term representation is more precise. When we think about things, whether through perception, imagination, memory, or desire, we represent those things. What is represented may be something present and real, or it may be fictitious, imagined in the future, or remembered from the past. Representations may even be unconscious. That is, the mind may have some defined content that is directed toward an object without the person being aware that they have produced such a representation. During the process of representation, even in a relatively simple case of visual perception, the brain makes a complex set of inferences. For instance, consider the checkerboard below. You might imagine that when you perceive something like a checkerboard, your brain passively takes a mental picture of the grid. In this analogy, the eye functions like the lens of a camera, and the brain develops the picture to present to the mind. But there are several problems with this model. First, where is the picture in your brain? Who is viewing the picture in your head? There are further problems with the camera analogy that can be revealed when we examine optical illusions. Look at the checkered set of squares in Figure 2.2. Are the horizontal lines parallel? Figure 2.3 The horizontal lines on this grid are parallel, but unless you look at the image from the side, it is impossible to “see” this. This is one of many examples of common perceptual illusions. (credit: “Optical Illusion” by Selena N. B. H. CC BY 2.0) In fact, the horizontal lines are parallel, but unless you look at the image from the side, it is impossible to visualize this. There are countless examples of these types of perceptual illusions. We represent the world outside as a stable picture that is completely filled in, in full focus, and uniformly colored. In reality, our visual field is limited and hazy around the edges, and colors change dramatically depending on lighting conditions, distance, movement, and a host of other factors. In fact, your brain is not passively capturing the world, like a camera, but is actively projecting the world so that it makes sense to you. Neuroscientist David Eagleman (2011) uses the analogy of the front page of a newspaper to describe how perception works. The front page is a representation of the world’s events for a given day. Of course, it does not present a full or complete picture of the world, but a summary intended to highlight the events of consequence, those that have changed, and those that we are most likely to care about. Like a newspaper editor, your brain is working overtime to project an image of the world based on what is relevant to your survival. You unconsciously adjust the images you perceive to give you the impression that they are far away, nearby, moving, and so forth. Instead of the fully formed, three-dimensional image of the world we seem to see, we actually perceive a kind of sketch, highlighting what we need to know to navigate safely in our environment and obtain what we need. You probably think that sense perception is the clearest and most certain way you can know the world around you. As the adage says, “Seeing is believing.” To become a better critical thinker, however, you will need to become skeptical of some of your basic beliefs. There are times when you absolutely should not believe your lying eyes. Emotions and Reason: Homeostasis and Allostasis In addition to the editorial license of mental representation, thinking is not always as rational as we imagine. The neuroscientist Antonio Damasio (1994) was one of the first to popularize the notion that rational thought is tempered by emotions. He is critical of what he perceives as the philosophical bias against emotion in the history of philosophy. In Descartes’ Error, he says modern philosophers have neglected the role of emotions in thought, imagining that the goal of rational thinking is to eliminate the influence of emotions. Instead, his years of clinical work with patients revealed to him that emotions cannot be separated from reason. Our most rational thoughts are, in fact, guided, informed, and influenced by emotions. According to Damasio, reasoning and intelligence function best when we care about something. Without feelings, says Damasio, we are less rational, not more rational. Damasio (1994) explains that emotions serve to maintain homeostasis in the brain through the chemical messengers known as neurotransmitters. Homeostasis is the biological tendency to find a neutral state of equilibrium (the word stasis means “standing still,” and homeo means “same or similar”). This process relies on a feedback loop where current bodily states are monitored, observed, and then altered to bring the body back into balance. Most homeostatic processes in the body are unconscious, but emotions are linked to conscious awareness. For instance, when your blood sugar is low and your body needs calories, there is a series of chemical processes that give rise to the feeling of hunger. This is a conscious signal that you need to eat; it promotes behavior that ensures survival. Similarly, a rustling sound in the bushes at night will trigger a series of physiological responses (heightened senses, increased heart rate, pupil dilation, etc.) that correspond to the feeling of fear and promote behavior, such as fight or flight, that are necessary for survival. What Damasio demonstrates is that emotions have their own feedback mechanism, so that an idea or image can generate physiological responses even in the absence of an external stimulus. Because emotional responses and conscious thought are closely linked, decision-making can be influenced by this emotional-physiological feedback mechanism. Our thinking can go astray because we are afraid of bad outcomes, and that fear dominates a more rational calculation about which course of action is most beneficial (1994, 172–175). In addition to maintaining equilibrium, the brain also anticipates future events and circumstances by projecting likely scenarios based on a catalog of past experiences and concepts generated through social norms and social interactions. The process of regulation that prepares the body to anticipate future needs before they arise is called allostasis (allo means “other or different”). Psychologist Lisa Feldman Barrett (2017) explains that the brain stores neural pathways that are triggered by external or internal stimuli to provide the closest match to the current situation. The neural pathways form a kind of template of action, promoting behavior like increased heart rate, pupil dilation, or motion. Feelings are a goal-oriented response to certain situations: they prepare us to behave and react in certain ways that promote what is beneficial to the body and sharpen and shape our awareness of the world. In summary, the brain makes inferences about the world through perceptions, emotions, and concepts that are largely unconscious and deeply ingrained in our psyches. This process allows us to navigate fluidly and accurately through a world with so many and varied stimuli. Our reactions to stimuli are partially homeostatic, meaning that the body tends to bring itself back into an optimal state of equilibrium, and partially allostatic, meaning that the body prepares for and anticipates future situations. Together, these impulses construct a picture of the world that we experience seamlessly and dynamically. Our experience is far more complicated than the crude mental model we imagine. We are projecting and constructing the world we experience as much as we are recording and viewing it. And that fact has important consequences for the kind of reflective and critical thought we ought to engage in when we try to think clearly about the world.