Subjectivity is an ability, the capacity to use a new inner mode of presenting the fact that you currently know something to yourself.

The self is not a thing, but a process.

As modern-day neuroscience tells us, we are never in touch with the present, because neural information-processing itself takes time. Signals take time to travel from your sensory organs along the multiple neuronal pathways in your body to your brain, and they take time to be processed and transformed into objects, scenes, and complex situations. So, strictly speaking, what you are experiencing as the present moment is actually the past.

Only as long as we believe in our own identity over time does it make sense for us to make future plans, avoid risks, and treat our fellow human beings fairly - for the consequences of our actions will, in the end, always concern ourselves.

One of the interesting characteristics of the Ego Tunnel is that it creates (as Finnish philosopher Antti Revonsuo called it) a robust "out-of-the brain experience", a highly realistic experience of not operating on internal models, but of effortlessly being in direct and immediate contact with the external world - and oneself.

For a human being, to possess a consciously experienced first-person perspective means to have acquired a very specific functional profile and distinctive level of representational content in one's currently active phenomenal self-model: It has, episodically, become a dynamic inner model of a knowing self.

As a first-order approximation, I would say that phenomenality is "availability for introspective attention": Consciousness is a property of all those mental contents to which you can in principle direct your attention.