In my view they are not “difficult” problems. They are impossible to solve and there reasons why.
There is an ambiguity on the meaning of consciousness at the very start. We can identify this ambiguity as medical vs philosophical consciousness.
Medical consciousness is when a patient reacts, shows behaviours that are related to the environment and to their body. For example, a doctor can ask a patient “Do you know where you are?” If the patient answers correctly, for example “I am at the hospital”, the patient is considered conscious. The problem with this kind of consciousness is that, being based on science, since medicine, doctors and hospitals are based on science, it is a mechanical concept. According to this definition, we can say that today all our smartphones have consciousness, because they have sensors and other advanced features, especially now with AI, that make them possible to give the correct answer “I am at the hospital”. Despite this evident flaw inherent in this concept, it is still in the background of many discussions on consciousness, making them very confused and difficult to deal with.
The philosophical concept is confused as well, because it mixes the “medical” concept with another concept that is connected to art, humanities and personal experience.
This means, in my opinion, that, if we want some philosophical clarity about consciousness, we need, once we have identified the medical meaning, to isolate the other one, that is the one connected to art, humanities and personal experience.
There is another ambiguity in this context, that is the ambiguity of the meaning of “subjectivity”. It reflects the ambiguity I have described about consciousness.
A simple way to understand subjectivity is temperature: feeling cold or hot is subjective, saying 36 Celsius degrees is objective. The problem with this distinction is that even feeling cold can be identified as objective, thanks to relativity. You feel cold because your natural body temperature is around 36 Celsius degrees, while external temperature is now 5 Celsius degrees. With this criterion, whenever we talk about any kind of subjectivity, it can always be reduced to objectivity. This false subjectivity, that actually is still objectivity, creates confusion in discussions.
There is another meaning of subjectivity, that is related, like consciousness, to art, humanities and personal experience. In this context consciousness and subjectivity are almost coincident. This particular meaning of consciousness and subjectivity exists just because some people have talked about it, but it is impossible to get any objective evidence of its existence. In this sense it is like ghosts, gods, spirits, angels and anything magic and supernatural: they might exist, just because there are people who talk about them, but we have no evidence of them.
I think that there is a difference between, on one side, the human experience of subjectivity and consciousness and, on the other side, ghosts, although we haven’t objective evidence of this difference either. We feel like we can feel our personal experience of self consciousness and subjectivity before any reflection, before any reasoning. On the contrary, talking about ghosts, gods, spirits, angels and similar things needs some mental elaboration, some reasoning to build the concept of them.
This makes me think that this other meaning of consciousness and subjectivity, that is related to art, humanities and personal experience, is true subjectivity. It is true because the other one, as I said, can be reduced to objectivity.
This true subjecivity, since it is pure subjectivity, is absolutely impossible to objectify. This is the reason why it is impossible to find evidence of it and even to talk about it. When we try to talk about it, as I am doing now, we can only rely in a hope that others will be able, successful, at finding in themselves a similar experience.
This impossibility to objectify is a limit, but is as also, actually, a tremendous resource. It is a limit, because we will never be able to “touch” or “see” each other’s experience of subjectivity. We can only trust, hope, believe in the existence of it in us and in other people. But it is also a tremendous resource, because it is what makes you a non-object, which mean a person, with a particular dignity. The moment you work on this kind of consciousness, try to cultivate it, to have some intuitive understanding of it, try to share it, listen to it, you are cultivating your being a human, a being that can hope to be “not-just-an-object”. The moment you just do a job, work like a machine, or even do philosophy with a mind centered on objectivity, you are being an object, just an object, that is on the way of loosing any higher dignity, humanity, empathy, growth, hope, art. That moment you are just a machine.
This means that the moment you try to understand subjectivity asking “What is it? How does it work? What makes it exist?” you are a machine that tries to objectify everything. But, as I said, true subjectivity is impossible to objectify, so that you will always feel that it is a “hard” problem. It escapes, and always will, your attempt to imprison it into a cage of concepts and reasoning.