We can hardly think of ourselves as living persons without referring to consciousness. In fact, we normally define ourselves through two features of our life: we are awake (the level of our consciousness is more than zero), and we are aware of something (our consciousness is not empty).
While it is quite intuitive to think that our brains are necessary for us to be conscious, it is tempting to think that looking at what is going on in the brain is enough to understand consciousness. But empirical investigations are not enough.
Neuroscientific methods to investigate consciousness and its disorders have developed massively in the last decades. The scientific and clinical advancements that have resulted are impressive. But while the ethical and clinical impacts of these advancements are often debated and studied, there is little conceptual analysis.
I think of one example in particular, namely, the neuroscience of disorders of consciousness. These are states where a person’s consciousness is more or less severely damaged. Most commonly, we think of patients in vegetative state, who exhibit levels of consciousness without any content. But it could also be a minimally conscious state with fluctuating levels and contents of consciousness.
How can we explain these complex conditions? Empirical science is usually supposed to be authoritative and help to assess very important issues, such as consciousness. Such scientific knowledge is basically inferential: it is grounded in the comparative assessment of residual consciousness in brain-damaged patients.
But because of its inferential nature, neuroscience takes the form of an inductive reasoning: it infers the presence of consciousness starting from data extracted by neurotechnology. This is done by comparing data from brain damaged patients with data from healthy individuals. Yet this induction is valid only on the basis of a previous definition of consciousness, a definition we made within an implicit or explicit theoretical framework. Thus a conceptual assessment of consciousness that is defined within a well-developed conceptual framework is crucial, and it will affect the inference of consciousness from empirical data.
When it comes to disorders of consciousness, there is still no adequate conceptual analysis of the complexity of consciousness: its levels, modes and degrees. Neuroscience often takes a functionalist account of consciousness for granted in which consciousness is assumed to be equivalent to cognition or at least to be based in cognition. Yet findings from comatose patients suggest that this is not the case. Instead, consciousness seems to be grounded on the phenomenal functions of the brain as they are related to the resting state’s activity.
For empirical neuroscience to be able to contribute to an understanding of consciousness, neuroscientists need input from philosophy. Take the case of communication with speechless patients through neurotechnology (Conversations with seemingly unconscious patients), or the prospective simulation of the brain (The challenge to simulate the brain) for example: here scientists can give philosophers empirical data that need to be considered in order to develop a well-founded conceptual framework within which consciousness can be defined.
The alleged autonomy of empirical science as source of objective knowledge is problematic. This is the reason why philosophy needs to collaborate with scientists in order to conceptually refine their research methods. On the other hand, dialogue with science is essential for philosophy to be meaningful.
We need a conceptual strategy for clarifying the theoretical framework of neuroscientific inferences. This is what we are trying to do in our CRB neuroethics group as part of the Human Brain Project (Neuroethics and Neurophilosophy).