Editing Mind–body dualism (section)

===Argument from personal identity===
This argument concerns the differences between the applicability of [[counterfactual conditionals]] to physical objects, on the one hand, and to conscious, personal agents on the other.<ref name="MG">Madell, G. 1981. ''The Identity of the Self''. Edinburgh: Edinburgh University Press.</ref> In the case of any material object, e.g. a printer, we can formulate a series of counterfactuals in the following manner:

# This printer could have been made of straw.
# This printer could have been made of some other kind of plastics and vacuum-tube transistors.
# This printer could have been made of 95% of what it is actually made of and 5% vacuum-tube transistors, etc..

Somewhere along the way from the printer's being made up exactly of the parts and materials which actually constitute it to the printer's being made up of some different matter at, say, 20%, the question of whether this printer is the same printer becomes a matter of arbitrary convention.

Imagine the case of a person, Frederick, who has a counterpart born from the same egg and a slightly [[genetically modified sperm]]. Imagine a series of counterfactual cases corresponding to the examples applied to the printer. Somewhere along the way, one is no longer sure about the identity of Frederick. In this latter case, it has been claimed, ''overlap of constitution'' cannot be applied to the identity of mind. As Madell puts it:<ref name="MG" />

:But while my present body can thus have its partial counterpart in some possible world, my present consciousness cannot. Any present state of consciousness that I can imagine either is or is not mine. There is no question of degree here.

If the counterpart of Frederick, Frederickus, is 70% constituted of the same physical substance as Frederick, does this mean that it is also 70% mentally identical with Frederick? Does it make sense to say that something is mentally 70% Frederick?<ref>Shoemaker, S., and [[Richard Swinburne]]. 1984. ''Personal Identity''. Oxford: Blackwell.</ref> A possible solution to this dilemma is that of [[open individualism]].

[[Richard Swinburne]], in his book ''The Existence of God'', put forward an argument for mind-body dualism based upon personal identity. He states that the brain is composed of two hemispheres and a cord linking the two and that, as modern science has shown, either of these can be removed without the person losing any memories or mental capacities.

He then cites a thought-experiment for the reader, asking what would happen if each of the two hemispheres of one person were placed inside two different people. Either, Swinburne claims, one of the two is me or neither is—and there is no way of telling which, as each will have similar memories and mental capacities to the other. In fact, Swinburne claims, even if one's mental capacities and memories are far more similar to the original person than the others' are, they still may not be him.

From here, he deduces that even if we know what has happened to every single atom inside a person's brain, we still do not know what has happened to 'them' as an identity. From here it follows that a part of our mind, or our soul, is immaterial, and, as a consequence, that mind-body dualism is true.<ref name="SR">[[Richard Swinburne|Swinburne, Richard]]. 1979. ''The Existence of God''. Oxford: Oxford University Press.</ref>

[[Christian List]] argues that Benj Hellie's [[vertiginous question]], i.e. why people exist as themselves and not as someone else, and the existence of first-personal facts, are a refutation of physicalist philosophies of consciousness. List argues that first personal facts cannot supervene on third personal facts. However, List also argues that this also refutes standard versions of mind-body dualism that have purely third-personal metaphysics.<ref>{{cite web |url=https://philpapers.org/rec/LISTFA |title=The first-personal argument against physicalism |last=List |first=Christian |date=2023 |website= |publisher= |access-date=3 September 2024 |quote=}}</ref>