by Marcus Loane
Consciousness is sometimes claimed to be outside the realm of science. It is true that there is no precise definition or proof of consciousness, but the same can be said of life and other areas that are open to scientific explanation. Proof is not needed, evidence is sufficient.
I think there can be physical evidence for consciousness which makes it testable and brings it into the realm of science. We assume that other people are conscious and we do it almost automatically. That in itself does not mean we are correct. However it is possible to use argument to show that it is a reasonable assumption. It goes as follows:
IF we assume that another person is conscious THEN we can make testable predictions about their behaviour based on that assumption.
We do that every day and it works most of the time. We predict the behaviour of others based on the assumption that they are having an inner experience similar to us. The fact that it is such a successful strategy is evidence (but not proof) that the assumption is correct.
We can never experience what it is like to be another person or another animal, but that does not mean we cannot know anything about what it is like. We can obtain some idea of what it may be like by observing behaviour and internal structure and processes of the other entities. For example if a dog has an inner experience, we know that it has no experience of colour because it does not have the necessary parts in its eyes to distinguish between different wavelengths of light. We could assume that blind-from-birth people also have no experience of colour.
Do not let anyone tell you that is impossible in principle to tackle the issue of consciousness. Once consciousness is better understood in humans then some of that knowledge (which structures, which processes) can be extrapolated to other species and entities.