"The condition necessary for the act of recollection, is the identity of the being who remembers, with that being whose former states are recalled by memory. To remember experiences of another would be to remember having been somebody else: in other words, to simultaneously affirm and deny one's own identity, a pure and absurd contradiction" (Amédée de Margerie, cited by Michael Maher in "Psychology")

How do I know that the subject of my memories and me are the same person? I have a memory of waking up this morning. How do I know that the subject who woke up, and the subject remembering it, are the same person?

I think I might have come across the beginning of an "argument" for the sameness of the subject that remembers some event and the subject that experienced that event.

Let's start with a principle that says that to feel or sense what Jack feels or senses, you have to be Jack. Well, when you remember some event, you remember the sensations felt by the subject of that first person experience. So, you seem to remember being someone else. But I don't really know how to develop the argument from here.

Any thoughts?

  • Everything here depends on how you define "the same person". There are at least three ways I can think of to define that. What's yours?
    – Chelonian
    Commented Apr 28, 2018 at 16:13
  • Where you read "the same person" you might as well read "the same self". Commented Apr 28, 2018 at 16:41
  • That's just a synonym. What's the definition? It's not as easy as you think to define this, but it's critical if you're asking about it.
    – Chelonian
    Commented Apr 28, 2018 at 17:18
  • I know it is certainly not easy. I accept the definition of person as an individual substance of a rational nature. Commented Apr 28, 2018 at 19:07
  • Possible duplicate of Memory and self
    – Chelonian
    Commented Apr 29, 2018 at 16:08

4 Answers 4


The infinite divisibility of doubt never led to anywhere really useful, which is why both Al-Ghazali and Descartes rather quickly left for greener and more fertile pastures.

If you are interested in a detailed conceptual and philosophical understanding of the self you could turn to Kant in the Western tradition and Nagarjuna in the Eastern tradition.

This does actually mean reading them. Obviously the primary sources are best. But generally people start with the recognised canonical commentators.


We only have subjective distinctions of our feelings to communicate them to ourselves and others. The feelings, and the words we use to describe what we are sensing, could be altered by our ability to think and speak of them. But, the question you are struggling to find reveals the core philosophical problem directly related to the Cartesean dualistic dilemma. Descartes methodology begins with doubt of what we know to be 'facts'. Which is great for deconstruction /construction from what we believe, to what we can prove. The downside of that is that it fractured the solid identity formulation the Greeks provide us with from ‘Psyche’. Psyche was/is the integrity of the individual; “The totality of the human mind, conscious and unconscious.”

Imagination is a wonderful, and often untethered, human characteristic.

As a dean of my Art School once said, “I am always leery of spontaneous ideas, because there are so many of them running around loose.”

  • Found this while researching another philosophical reference. ‘The identity we ascribe to the mind of man is only a fictitious one.’ (David Hume 1739 – 40). Commented Apr 29, 2018 at 14:35

You character changes. Consider say, you wake up with a different balance of hormones, shorter tempered. Or short on serotonin, depressed. You might behave and react very differently. When brain hemispheres are disconnected for medical reasons, it reveals how much of our behaviour is from non-conscious impulses, which we consciously rationalise, so a lot of our motivations are not in the part of us we identify with being ourselves.

The information in your brain is still focused around a specific trail of subjectivity, affected by how others percieved you (appearance etc). To other people, you are a certain shape of thing, and following brain death or lobotomy, or even brain transplant they would see the same thing as present. And almost all of our cells get replaced, the whole ship of Theseus.

That still leaves memories. Which are like available subjective stories. Once we have good vr films or immersive games, it may be that memories could equally be ours, or someone elses/told from another character's view.

We just have now. Memory, character, appearance, they are just information, not 'you', that can be brouggt to bear in a given now. When that becomes memory, it also 'not you'.

Older you is different to younger you. Every day you wake up as someone else. Each breathe, who you were passes from the world, and the capacity for you to choose who to be now is there ahead, like a doorway always just opened.


There are no entities and identities on the physical universe. It's all in our heads. The universe is just a set of interactions (Feynman: mass is interaction).

We create the notion of thing in order to interact, and our reason allows us to make a history of things, to model them and think of them as units. Things exist only in your head. A river is only an interaction, always changing. But in our mind, it is a concrete idea. Persons are just things. They are like the river, every instant changing, mutating, evolving. But not in our mind. If you want more, see the systems theory or my book.

So, you are the same person you see in the mirror (whatever that might mean) just due to your reason. All ideas are subjective. A lot of philosophers agree that objectivity is not really possible: it is all a shared subjectivity.

Regarding feeling like Jack, that's called empathy. Your mind can make you actually feel pain if you see somebody walking on a rope. You are in a safe place, you're not falling down. But you can understand his situation and feel like you are on his shoes.

It's all part of our toolset to survive.

Note, in your formulation, you're already assuming objectivity as a fact and assuming that your approach on identity is correct. Both assumptions are arguable; without them, you're forced to address the underlying issues.

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