Our mind seems to be immaterial. This is our undeniable everyday experience. Our mind seems to refer to and be aware of external and internal, abstract and concrete entities effortlessly and without any perceived material machinery. We perceive the external world; tables, chairs, books, whatever, directly without the awareness of any intermediate symbols or representations. On the other hand our physical responses are definitely material, yet initiated and controlled by our immaterial mind. We get the mind-body interaction problem: How can something immaterial control material processes? This problem is carried over to robotics, too. A conscious robot should also have an immaterial robot mind that can control the material body. This would seem to be next to impossible and we are stuck with the mind-body problem. Any successful design proposal for conscious machines must also propose a solution to this problem.
Immaterial minds cannot be created by material means; this is true by definition. If mind was indeed immaterial then obviously any material construction effort would fail and our work would be futile. We can go on only if we assume that in reality mind was based on carrying material symbols and processes, but how could this be given our everyday perception of the contrary?
What evidence do we have about the immaterial nature of mind? We have our subjective perception only; we are not aware of any material processes behind our thinking and consciousness. However, for the observer self the appearance of mind "without the awareness of any carrying material symbols or processes" and "without any carrying material symbols or processes" can be the same. Therefore, the missing perception of material carrying symbols or processes does not prove that these would not exist. Yet, for centuries common people and philosophers alike have made this logically unsound conclusion, which in turn has led to the idea of immaterial mind.
If our mind is actually material then why can't we perceive the material machinery behind it? Or, what would it take for us to be able to perceive the machinery, the neural firings, etc.? It seems that whatever it takes we do not have and the material machinery remains beyond our introspective powers. The material carrier mechanism remains transparent to us and we perceive the carried information only; the percept of an object is the symbol for that object.
This view offers design guidance for conscious machines. Machine minds that appear as immaterial to the machine self can be created if the information representation and processing method supports carrier medium transparency.