IB Philosophy 1.2.2 Solipsism and Inter-subjectivity Notes

Situating the Question: From Self to Other

1. These definitions are essential to understanding the discussed topics below. Ensure that you understand them.

The Self-Other Problem

1. In 1.2.1, we asked whether the self exists at all.
2. Section 1.2.2 assumes we have at least a provisional answer and presses further: even if I exist as a self, can I know myself? And can I know that any other self exists beyond my own experience?
3. These are the twin questions of this topic: Can we really know ourselves? Can we really know the other?
4. Together, they open one of the most unsettling problems in philosophy: the possibility that each of us is trapped inside our own experience, with no way out to verify whether anything beyond it actually exists.
5. Solipsism takes this problem to its most extreme conclusion: only your own mind can be known with any certainty to exist.
6. Everything else, including other people and the external world, might be a construction of one's own experience with no independent existence to verify.
7. Solipsism is philosophically significant not because it is widely held (almost no philosopher sincerely endorses it as a lived position) but because it is remarkably difficult to refute. Engaging with it forces us to clarify what we mean by knowledge, evidence, and the existence of minds other than our own.

The Intersubjective Response

1. The intersubjective tradition pushes back: the self is not sealed off but is shaped by its relationships with others. Husserl laid the groundwork with his concept of appresentation (a kind of co-presence): when we see another person move or speak, we do not just observe their body, we directly sense their inner life as present alongside it, even though we cannot perceive it as we perceive our own.
2. Building on Husserl, Maurice Merleau-Ponty and Simone de Beauvoir developed the phenomenological response to solipsism further.
3. Simone de Beauvoir is the required philosopher for this topic. Drawing on existentialism and phenomenology, she argues that the solipsistic conception of the isolated, self-sufficient self is not only philosophically untenable but ethically dangerous.
4. These questions connect backward to the identity topics in 1.1: if the self is partly constituted by cultural identity (1.1.3) and relational practices (as Jonardon Ganeri argued in 1.2.1), then self-knowledge requires understanding the social and cultural frameworks that shape us, not just introspection.
5. They connect forward to the problem of other minds (1.3.3), which is the epistemological version of the question: how can I ever know, with certainty, that any other mind actually exists? And to relations to others (1.2.3), which explores the concrete forms that self-other relationships take.
6. For IB Philosophy students, this topic develops the analytical vocabulary of solipsism, intersubjectivity, and recognition, terms that recur across questions on consciousness, freedom, and ethics throughout the IB syllabus.

The Solipsist Challenge

Cartesian Origins and the Problem of Other Minds

1. The roots of the solipsist problem lie in Rene Descartes' method of radical doubt, articulated in the Meditations on First Philosophy (1641).
   1. By systematically doubting everything that could be doubted, Descartes arrived at the cogito: I think, therefore I am.
2. The cogito establishes the existence of one thinking mind with certainty: Descartes' own.