Key Arguments

• Parfit summarizes Descartes’s move: 'Even if we are not directly aware of the existence of these entities, some claim that we can deduce their existence from any of our experiences. Descartes, famously, made such a claim. When he asked if there was anything that he could not doubt, his answer was that he could not doubt his own existence. This was revealed in the very act of doubting. And, besides assuming that every thought must have a thinker, Descartes assumed that a thinker must be a Pure Ego, or spiritual substance.'
• He identifies Descartes’s error as Lichtenberg saw it: 'Lichtenberg claimed that, in what he thought to be most certain, Descartes went astray. He should not have claimed that a thinker must be a separately existing entity. His famous Cogito did not justify this belief.'
• As alternative, Lichtenberg suggests reformulations that avoid 'I am' as a thinker: 'He should not have claimed, I think, therefore I am’. Though this is true, it is misleading. Descartes could have claimed instead, ‘It is thought: thinking is going on’. Or he could have claimed, ‘This is a thought, therefore at least one thought is being thought’.' These formulations assert the occurrence of thought without positing a subject.
• Parfit grants that 'Because we ascribe thoughts to thinkers, we can truly claim that thinkers exist. But we cannot deduce, from the content of our experiences, that a thinker is a separately existing entity.' So ordinary ascriptions do not license Cartesian metaphysics.
• He then draws the impersonal description conclusion: 'And, as Lichtenberg suggests, because we are not separately existing entities, we could fully describe our thoughts without claiming that they have thinkers. We could fully describe our experiences, and the connections between them, without claiming that they are had by a subject of experiences. We could give what I call an impersonal description.'

Source Quotes

This was revealed in the very act of doubting. And, besides assuming that every thought must have a thinker, Descartes assumed that a thinker must be a Pure Ego, or spiritual substance. A Cartesian Pure Ego is the clearest case of a separately existing entity, distinct from the brain and body.

A Cartesian Pure Ego is the clearest case of a separately existing entity, distinct from the brain and body. 19 Lichtenberg claimed that, in what he thought to be most certain, Descartes went astray. He should not have claimed that a thinker must be a separately existing entity.

19 Lichtenberg claimed that, in what he thought to be most certain, Descartes went astray. He should not have claimed that a thinker must be a separately existing entity. His famous Cogito did not justify this belief.

His famous Cogito did not justify this belief. He should not have claimed, I think, therefore I am’. Though this is true, it is misleading. Descartes could have claimed instead, ‘It is thought: thinking is going on’.

Though this is true, it is misleading. Descartes could have claimed instead, ‘It is thought: thinking is going on’. Or he could have claimed, ‘This is a thought, therefore at least one thought is being thought’.20 Because we ascribe thoughts to thinkers, we can truly claim that thinkers exist.

Descartes could have claimed instead, ‘It is thought: thinking is going on’. Or he could have claimed, ‘This is a thought, therefore at least one thought is being thought’.20 Because we ascribe thoughts to thinkers, we can truly claim that thinkers exist. But we cannot deduce, from the content of our experiences, that a thinker is a separately existing entity.

But we cannot deduce, from the content of our experiences, that a thinker is a separately existing entity. And, as Lichtenberg suggests, because we are not separately existing entities, we could fully describe our thoughts without claiming that they have thinkers. We could fully describe our experiences, and the connections between them, without claiming that they are had by a subject of experiences.

And, as Lichtenberg suggests, because we are not separately existing entities, we could fully describe our thoughts without claiming that they have thinkers. We could fully describe our experiences, and the connections between them, without claiming that they are had by a subject of experiences. We could give what I call an impersonal description.

We could fully describe our experiences, and the connections between them, without claiming that they are had by a subject of experiences. We could give what I call an impersonal description. As I have said, some writers reject both this last Reductionist claim and the Cartesian View.

Key Concepts

• Descartes assumed that a thinker must be a Pure Ego, or spiritual substance.
• Lichtenberg claimed that, in what he thought to be most certain, Descartes went astray.
• He should not have claimed that a thinker must be a separately existing entity.
• He should not have claimed, I think, therefore I am’. Though this is true, it is misleading.
• ‘It is thought: thinking is going on’.
• ‘This is a thought, therefore at least one thought is being thought’.
• we could fully describe our thoughts without claiming that they have thinkers.
• We could fully describe our experiences, and the connections between them, without claiming that they are had by a subject of experiences.
• We could give what I call an impersonal description.

Context

In the middle of Section 81, Parfit recounts Descartes’s cogito and Lichtenberg’s objection, using it to support the Reductionist idea that mental life can in principle be described without invoking a substantial subject of experience.