First, a few questions to consider: do animals have minds and perspectives? Do all humans in the waking realm? Do dream characters? How about demons and angels encountered in magickal workings? Did you have a mind and a perspective in the past? Will you in the future?
Second, let's remember that, conventionally, no one knows whether or not other people have minds and perspectives (or 'subjectivity' or 'consciousness'). It's impossible in principle, according to human convention, to actually access the mind and perspective of another human. Otherwise, we wouldn't have distinct minds and perspectives. No amount of brain science on others and no amount of conversation with others can definitely answer that question, just like no amount of science can prove that this is a real, external material reality and not an illusory, internal mental reality.
So, whether or not there are other minds is a matter of perspective, like the question of whether or not there is a material world. And like with a material world, the difference between believing and not believing is not a matter of whether or not there are actually other minds. It's a matter of whether you are manifesting your imagination and experience in such a way that it you have experience suggestive of other minds or not.
There is a difference in the way that humans relate to and manifest dream people v. waking people. Generally, humans consider dream people to be mindless and okay to toy with and generally consider waking people to be minded and important to treat with respect. To make the point even stronger, some people consider waking animals to have perspectives and others do not.
Now, imagine that you could telepathically read and influence other people's perspectives. How might that work? It could turn out that their perspectives were accessible and adjustable to you in a way similar to the way that your memories of your past perspectives are accessible and adjustable to you. That would mean that their perspectives are not distinct objects from your mind, but are unconscious aspects of your perspective that you can focus on like your memories. However, in this view, that also means that what you presently identify as your human perspective is only another aspect of your mind that you are accustomed to focusing on more than other aspects of your mind.
Further, imagine that in this state you decided that you didn't like always controlling and knowing other peoples's perspectives. You actively practiced focusing on what we ordinarily call your human perspective without ever focusing on the other perspectives. Imagine that after doing this for thousands of lifetimes you forgot that you weren't just this perspective and forgot that you could read and influence apparently other perspectives – you start to regard them as other. Your perception of the perspectives of others would be essentially what your perception of others is now, abstractly. You would think that those unconscious aspects of your mind were other than you, and you would be mistakenly identifying your mind with your human role, like a person can mistakenly identify with their job or personality or wealth.
Similarly, imagine that some other individual could telepathically read and influence your perspective. It would feel like your perspective was only an aspect of their mind. But, your perspective is an aspect of your own mind, so in this view, too, your minds must not be distinct. From your perspective, they are an aspect of your mind that you are unconscious of that you are at some level allowing to have an influential relationship with your conventional human perspective. From their perspective, you are an aspect of their mind as in the last example.
If we were to imagine that our perspectives had no telepathic influence on each other then we would not be able to interact with one another in any way. If we imagine that our perspectives were completely telepathically intertwined, then there would be no illusion of separation. However, in the conventional world, we imagine that our perspectives only telepathically influence each other in a limited manner – you can directly manipulate my perception of your body and I can directly manipulate your perception of my body. And we imagine that neither of us can directly manipulate either our own or each others's perception of the material world.
Imagine is the operative word here (you could replace it with 'believe' if you prefer). I imagine a perspective that I call you, and you imagine a perspective that you call me. I also imagine that you imagine a perspective that you call me, and you also imagine that I imagine a perspective that I call you. Your idea of other people and your idea of yourself as a person are only ideas in your mind.
Think about it like this. Your beliefs and memories and expectations and values and desires are all intentional mental structures. None of those are you at your core, because you could in principle have different memories or different desires and still be you. Now, imagine that all of your beliefs and memories and expectations and values and desires and all other aspects of your perspective were replaced with mine. Now, you and I are the same.
I only understand and interact with your perspective, with you, as a potential perspective that I could have that I do not. When I interact with you, I am only interacting with an aspect of myself. Similarly, when you interact with me, you are only interacting with an aspect of yourself.
So, in my view, there is only one mind. From my perspective, it is my mind. From your perspective, it is your mind. From any perspective, the mind is their own. So, in my view, there is no distinction between you or I at the level of mind. But there are infinite possible perspectives the mind can take which we can somewhat arbitrarily divide into categories like you, me, him, and her in the same way that we can somewhat arbitrarily divide the infinite colors into categories like blue, red, lavender, warm colors, etc.