About a year ago, I wrote an article about differentiating between explaining behaviour and describing it. Today, I add another layer to this reflection. What do we want to know when we ask for an explanation of a certain behaviour? For instance, if I wanted to know why John went to the kitchen, would I be satisfied with an answer ‘the respective neurons in his brain fired appropriately and sent the signals to his limbs’? I might be satisfied if I were a neuroscientist. But in everyday life, we want to know the motivation John had for going to the kitchen. Something like ‘because he was hungry and wanted to grab a snack from the fridge’. Yet, both explanations are valid. They are not mutually exclusive. This is what philosophers of mind refer to as two levels of explanation (of our behaviours): person level and sub-person level of explanations.
Person level explanations are those that are available to us upon introspection, we are/can be aware of them (what we call our mental states). On this level, we ask the question ‘why’ – why did I go to the kitchen? Because I felt hungry and I believed there is some food in my fridge. The ease with which we think in this manner and its widespread presence among human beings suggests that this sort of reasoning (level of explanation) is essentially important to us. On this level, we try to make sense of our environment and ourselves in it. It is a meaning-making level of explanation. Therefore, the crucial condition to qualify for this level of explanation is the availability of these mental states to my consciousness, as a good part of the person-level explanation has to do with our meaning/sense-making, and we cannot make sense of or find meaning in something we are not conscious of.
Sub-person level explanations are not available to us upon introspection, we cannot become aware of them ourselves (for instance, most of the biochemical processes in our bodies, neurons firing in our brains etc). The sub-person level of explanation asks the question ‘how’ – how this or that behaviour came about? Not ‘how’ in our every day, ‘folk’ sense of the word (which is another way of asking why), but in the process-focused, mechanical sense. How does this or that behaviour ‘work’, what is its structure, its architecture? On this level, I went to the kitchen by means of particular regions of my brain that are involved in the movement of limbs being active, coordinating signals with my limbs, maintaining balance, and so on.
The how doesn’t explain the why, and vice versa, but they both offer informative accounts of the same behaviour, just from different perspectives. One of the main philosophical problems, however, is how to fit both of these levels together into one account. Even if they do not explain each other, intuitively we feel there must be a connection between them, a way they play together and influence each other. This is referred to as the interface problem.
There is a variety of solutions proposed by philosophers and I will explore them in separate articles. Just to mention one for now – a position (represented, for instance, by philosopher Daniel Dennett) that suggests we cannot solve the interface problem because both levels of explanations ask fundamentally different questions, and they are, therefore, incommensurable (moreover, the personal level does not refer to any actual reality, according to Dennett, as the sub-person level does, and therefore can be regarded as a sort of illusion that cannot be analysed and explained).
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