Parfit v Johnston’s Further Fact View

Is Sylvie, Loki? Psychological criterion theory would argue that both characters are two individual people.

Parfit’s teletransportation problem splits the question of personal identity in two, with arguments falling on either side, in defence of or against the importance of personal identity. While Parfit provides that it is psychological continuity that matters in identity, he ultimately concludes that it is not personal identity that matters, but survival. As such, according to Parfit, the question of personal identity is irrelevant. However, other philosophers have disagreed with Parfit’s view that personal identity is unimportant. With the support of Johnston and Shoemaker, I argue that the nature, and therefore the question, of personal identity does matter and that there can only be one being who is uniquely you.

Hume, Locke and Parfit: The Foundations of Personal Identity

To correctly analyse the question of personal identity, we must first have an understanding of what personal identity actually is. There are two forms of identity that two prominent philosophers have discussed prior to Parfit. First, David Hume introduces us to Qualitative Identity through the bundle theory and argues that the concept of the self is ever-changing over time. That is, we are simply a bundle of impressions that are made up of various properties, form our body to our mind, emotions, personal preferences and memories. Counter to this; John Locke argues the memory theory, which provides that our identity persists over time because we remain in the same body and hold the same mind, and with this a chain of memories, from birth until death. That is, our identity is persistent with our Numerical Identity as a unique singularity of ourselves.

Parfit provides that it is numerical identity that is the scaffolding personal identity. He develops Locke’s theory further by providing for two criteria of identity: The physical criterion and the psychological criterion.

The Physical Criterion:

(1) It is not necessary for the whole body to continue to exist, but rather enough of the brain to be considered the brain of a living person. Person A will be regarded as the same as Person B at a past time if, and only if:

(2) A sufficient amount of B’s brain continues to exist, is now A’s brain; and

(3) A branching form has not taken place.

(4) Personal identity consists of holding facts (2) and (3) over time.

The Psychological Criterion:

(1) Psychological continuity is dependent on the existence of overlapping chains of strong psychological connectedness. Person A is the same person as Person B at a past time if, and only if:

(2) A is psychologically continuous with B; and

(3) This continuity has the right kind of cause; and

(4) A branching form has not taken place.

(5) Personal identity consists of holding facts (2) and (4).

Parfit defends his reductionist approach by reasoning that our identity is not always conclusive and rejects the notion of the Cartesian Ego, which is the idea that we exist as a separately existing entity such as a soul, spirit or form of consciousness that can exist outside of the body. Further, he predominantly argues that it is psychological continuity and connectedness (R-relation) that ensures that our survival prevails over personal identity in regards to importance.

However, condition (3) of the psychological criterion raises questions over the definition of the right kind of cause. Parfit doubles down on his reductionist approach by providing that there are three readings of psychological criterion:

1. The Narrow reading provides that continuity be caused by normal conditions;

2. The Wide reading allows for causation to be any reliable cause; and

3. The Broad reading provides that any cause may be sufficient to cause psychological continuity.

The Narrow reading is the most logically sound when applied to the psychological criterion in the real world. Therefore, in the matter of the simple teletransportation problem — whereby there is only a singular version of yourself, the narrow reading provides that the replica on Mars would not be you, as you would be considered to have died in the machine, thus severing the chain of continuity. However, both the wider and broader readings provide that causation may be anything beyond the scope of normality. Therefore; your replica having carried on your R-relation, would be you.

However, when considering the branch-line case of the teletransportation problem, Parfit insists that we ought to care about the persistence of our psychology rather than the continued existence of ourselves in any other capacity. Further; when considering the troubling implications of our immediate death upon activating the machine, he goes on to say this:

If personal identity is what matters, I should regard my prospect here as being nearly as bad as ordinary death. But if what matters is Relation R, with any cause, I should regard this way of dying as being about as good as ordinary survival.

However, while Parfit defends the reductionist argument and dismisses the alternative of a Cartesian Ego, in applying the narrow reading to the psychological criterion, he fails to account for the fact that as human beings, we are transitive in nature and as such this nature prohibits us from being identical with each other. As such, I disagree with Parfit’s view that personal identity is unimportant and support Johnston’s further fact view.

The Further Fact View

Parfit’s argument starts with the assumption that identity is important, and as a reductionist, he naturally concludes that this assumption is false. However, this assumption does not fully support Parfit’s view that personal identity is completely irrelevant. Johnston views Parfit’s argument through this lens and argues that Parfit’s conclusion can only hold in severely indeterminate cases that are extremely unlikely to happen ­­– that is, only in the wider and broader readings.

As a non-reductionist, Johnston argues that there is an additional fact outside of the realm of psychological and physical continuity that ought to be considered when defining personal identity. He argues that if a fact consists entirely of other facts, then even if those facts do not matter, this does not negate the possibility that the predominant fact might still be relevant and the subordinate facts may only have derivative importance. Parfit counters this by arguing that the subordinate facts can only matter.

Johnston’s argument from above:

If A consists of B and C, then even if B and C are irrelevant, fact A might still hold relevance, in which case B and C will only have derivative importance.

Parfit’s argument from below:

If A consists entirely of B and C, it can only be B and C that matter.

Parfit concedes to Johnston’s argument by agreeing that his form of ontological reductionism, which considers entities to consist of a collection of more basic kinds of substances or objects, is compatible with the concept of a further fact. Johnston draws upon the science of microphysical particles to support his rationale by arguing that, considering that all facts of the world consist of facts about microphysical particles, to which we hold non-derivative concerns, then all values based on those facts shouldn’t’ matter either. Johnston holds this view to be absurd, as it is essentially arguing that no facts should matter in the grand scheme of things. Last, Johnston argues that Parfit’s position is guilty of a fallacy of composition. He provides that just because some portions of a larger fact hold no value does not mean that the larger fact of which the smaller facts consist of, also hold no value.

This latter argument is essentially an example of Aristotle’s Statue and Clay problem, to which I would argue that a statue formed out of a lump of clay, coincides with its originating form. That is, the lump of clay constitutes but is not identical to the statue.

At this point, it would appear that the contention of the argument is about which facts are conceptual and which are wholly constitutional to the question of identity. Johnston’s position is that if the argument for why identity does not matter is formulated on the assumption that identity is conceptual, then Parfit must step up to the bar and explain why this is so. In response, Parfit argues that this view priorities language over reality, but this response does not adequately address Johnston’s objection. Parfit appears to press that we must cease talking about personal identity at all, and in doing so avoids answering the direct question of Who exactly is Person B? In avoiding answering the question, he does little to support the conclusion that we ought not be concerned about personal identity.

In my view, Johnston holds the stronger position by highlighting that no satisfactory conclusion can be found in Parfit’s argument that personal identity does no matter. Parfit must either accept that there is an additional further fact to be considered and provide an argument that addresses the issues of conceptual and wholly constitutional facts of identity, or accept that the extreme outcome that all things in this world do not matter and hold no significance. Regardless, the avoidance of a question is not satisfactory enough to convince me that personal identity does not matter, and I continue to believe that there is and only ever will be a single version that is wholly and constitutionally me.

Brueckner, Anthony, ‘Parfit on What Matters in Survival’ (1993) 70(1) Philosophical Studies: An International Journal for Philosophy in the Analytic

Hershenov, David, ‘Countering the Appeal of the Psychological Approach to Personal Identity’ (2004) 39(3) Philosophy

Hume, David, A Treatise of Human Nature (Oxford: Clarendon Pres, Reprinted, 1896)

Locke, John, The Correspondence of John Locke, eight volumes, (Oxford: Clarendon Press, 1976–1989)

Parfit, Derek, Reasons and Persons, (Oxford: Clarendon Press, Reprinted 1987)

Parfit, Derek, The unimportance of identity, Identity (Oxford University Press 1995) 33

Pollock, Henry, ‘Parfit’s Fission Dilemma: Why Relation R Doesn’t Matter’ (2018) 85(4) Theoria 284–294

­­Shoemaker, David, ‘Parfit’s ‘Argument from Below’ v Johnston’s ‘Argument from Above’’, Politics, Philosophy and Economics (2006).

Shoemaker, Sydney, Parfit on Identity (Oxford:Blackwell, 1997) 135–148



Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Laura E Fox

Laura E Fox

LLB (Hons) and BA (Gender Studies and Philosophy) student. A collection of academic essays.