Monday, 14 July 2014

A Brief Summary of John Searle's "Minds, Brains and Science"

John Searle, the American philosopher and Professor at Berkeley, originally wrote his book Minds, Brains and Science as part of a lecture, or indeed a series of lectures called the 1984 Reith Lectures. In the concluding pages he writes that his aim has been to “characterise the relationships between the conception that we have of ourselves as rational, free, conscious, mindful agents with a conception that we have of the world as consisting of mindless, meaningless, physical particles.” Searle successfully tackles some very challenging questions (like The Mind-Body Problem, and The Problem of Free Will) by addressing previous solutions to the problems, pointing out their strengths and weaknesses, and then giving his own arguments using constant examples and reasons to support his argument, making his point of view more comprehensible to the reader. In this essay I am going to attempt to briefly summarise each of his arguments.

One point that repeatedly comes across throughout the book is that there are two levels of mentality: “a higher level in mental terms, and a lower level in physiological terms.” This means that the mind and consciousness can both be caused by the brain, and realised in the brain. He goes on to explain that there are two causally real levels of description in the brain: for example, at a higher level, the conscience’s intention raises the arm, but at a lower level, the neurons in the brain cause the arm to be raised. Thus he concludes the Mind-Body Problem by asserting his belief in both physicalism and mentalism: he believes that the mind and body interact, but that they are not two different things, since mental phenomena are features of the brain. This, incidentally, has parallels with Aristotle’s beliefs about the soul. Aristotle, although he was a dualist, did not believe that the soul and the body were entirely independent of one another.

Searle’s solution to the question “Can computers think?” is also particularly interesting. He very successfully articulates what many philosophers have not been able to articulate in the past: that computers are defined by their formal or syntactical structure, whereas human minds have semantic contexts. Thus a computer is able to simulate thinking (i.e. by manipulating meaningless symbols without understanding them), but it is not able to think in the same way the human mind can think. In the next chapter, Searle effectively defeats all the arguments in favour of cognitivism (the belief that thinking is synonymous with processing information and symbol manipulation, suggesting that the mind is in fact very similar to the digital computer). He does not argue that the belief is completely false, but says that a distinction needs to be made between ‘psychological information-processing’ (which involves thinking) and ‘as if psychological information-processing’ (when there are no mental states at all). He also points out that many of the actions that are supposedly calculated, are actually just done by the brain automatically. There is therefore no need for unconscious calculation in addition to the level of our mental states (the level of intentionality) and the level of our neurophysiology. He writes: “The fact that a computational simulation of a natural phenomenon involves complex information-processing does not show that the phenomenon itself involves such processing…” and this is a major flaw of the brain-computer comparison. Thus he concludes that, although our mind does do calculations, they are not the same as the calculations that a computer does, and certainly there is no separate mental level for calculation.

In his Chapter “The Structure of Action” Searle goes in to a lot of depth about the idea of intentionality and the mental states of actions. He states that actions have two components (a mental one and a physical one), and that the mental component is an intention (i.e. a belief, desire, hope) and this causes the action. He refers to this form of causation as ‘intentional causation’, and the mental component has to both represent and cause the physical component. The intentions are also part of the explanation of an action (i.e. we can see why someone did something if we know their motives, and thus the content that causes the action is the same as the content in the explanation), and indeed some intentions can be formed during an action (i.e. when someone is acting spontaneously without prior reasoning). However, he asserts that all prior intentions are the product of practical reasoning and the weighing up of conflicting desires. He then goes on to explain that human intentions are formed with ‘the background of intentionality’. What he means by this is that our intentions are formed on our skills, habits and abilities etc. Searle concludes by saying that, despite the development of scientific accounts of behaviour, the commonsense explanation (like both his and Freud’s) will continue to persist and survive.

In his penultimate Chapter, Searle examines the restraints of the social sciences which, he argues, can also be seen as strengths of the social sciences. He gives a step-by-step argument explaining why the social sciences can never give us strict laws on human behaviour. He begins by saying that for their to be laws of the social sciences there has to be a systematic correlation between phenomena identified in social and psychological terms and phenomena identified in physical terms. He says that social phenomena are in large part defined in terms of the psychological attitudes that people take, and this means that there is no physical limit to what we might regard as money or a house, implying that there can be no bridge principles between the social and the physical features in the world. Finally, there can be no bridge principles between phenomena described in mental terms (the mind), and phenomena described in neurophysiological terms (the brain). Thus, he concludes, no rules for human behaviour can be found, since there is no fixed correlation between the phenomena described in social terms and phenomena described in physical terms. In conclusion he gives a brief description of the character of the social sciences, which he claims are firmly rooted in intentionality. He says that the social sciences (like economics or linguistics) are grounded in human practices, context and history, and that as these practices change, so the rules change. However, the main reason that no fixed rules can be given (he explains that the rules of economics are based on assumptions about the intentions of buyers and sellers etc.) for the social sciences is because they are powered by the mind and by human intentions. The only thing that social sciences can provide is, therefore, theories of pure and applied intentionality; they cannot provide rules.

John Searle then combines this idea of intentionality, and the idea of the mind being both part of the brain and caused by the brain, to answer the Problem of Free Will. In his final chapter he explains that science leaves very little room for the freedom of the will, and indeed he swiftly defeats the indeterminism argument. However, he then writes:

“There are all sorts of experiences that we have in life where it seems just a fact of our experience that though we did one thing, we feel we know perfectly well that we could have done something else.”

This, he says, is the most compelling argument for free will. He then explains the theory of ‘compatibilism’ (the belief that determinism and free will can both work together) and its major problem: that it does not allow for true free will, the idea that humans can choose between two acts, all other conditions remaining the same. He explains that our actions are caused by our mental states and neurophysiology, and thus one could still argue that all of our actions are determined at the basic micro-level of physics. However, it is the fact that we experience acting rather than perceiving, and the fact that our acts are determined by intentionality, that we are unable to shake the conviction of our own freedom. He uses the example of a man at gunpoint: although his actions are determined that he will almost certainly do as he is told, he can still choose to do otherwise, and he puts this down to human consciousness and intentionality. He claims that the experience of freedom is an essential component of any case of acting with an intention, and thus we arrive at a modified form of compatibilism: psychological libertarianism is compatible with physical determinism. Although we may be physically determined, our mind, our consciousness, our intentions, can never be determined, and thus we can never be said to be unfree. He says that we could never “discover that we do not at least try to engage in voluntary, free, intentional actions”.

Throughout his book, while tackling a number of problems, Searle persists in proving that our commonsense mentalistic conception of ourselves is perfectly consistent with our conception of nature as a physical system. He claims that, although we have discovered many of our commensense beliefs to be false (i.e. that the world is flat), our conception of our behaviour and ourselves will never be entirely wrong, since it is only ourselves who can understand the cause of our actions. Our reality comes from within ourselves, making it unlikely that our conception of our reality is completely false.


  1. I'm not sure he's right at all about computers. I suspect this is going to be one of those things that seemed like science fiction until they became real, and then seemed completely inevitable. People used to say space flight, and even regular heavier-than-air flight, were impossible, right until just before they happened. If you want to maintain that computers simply *cannot* think then you *must* commit to the idea of some kind of extra-reality "soul" or similar - if we maintain that the human mind is only matter arranged in an incredibly complex way, then it follows that there's no reason why other arrangements of other matter couldn't do the same things it can. Most philosophers are happy to maintain that computers can't think, without committing on the soul issue. If one accepts the existence of a soul, fine, but you can't have it both ways.

    I, on the other hand, think a soul is something that raises far more questions than it answers, and so am strongly inclined to reject it. I therefore think there's no reason why a computer - being just a complex arrangement of matter, like a human being - shouldn't one day be able to "think" in much the way we do (or rather, the way that we think we do). In fact, I'll go one step further, and say that some artificial intelligences actually *do* think, with at least the same level of intelligence as multicellular creatures like mussels or ants. They may be restricted to a limited sphere of contexts in which they can perform effectively, but that's the same with all thinking creatures (e.g. you can't put a bear in a spaceship).

  2. I suppose. But I think (unless I've already forgotten) that he does say that computers may be developed that CAN think. I agree with him in his belief that modern computers, that simply work by numbers, cannot think, but one day maybe a computer that functions like a human brain can be made (unless one has already been made). And as to the soul, I too don't believe in a soul. I do, however, believe in the mind.

  3. Sorry, I've just realised how incomprehensible that comment is - it's really late and I'm very tired!