Socrates' Arguments to Prove Soul is Immune to Death in Plato's Phaedo

Throughout Phaedo, Socrates uses a priori proofs coupled with logic to support his idea that the soul is immune to death and destruction, and will therefore continue to exist after the death of the body. He uses empirical science sparingly as his arguments deal with intangible objects and concepts for which no data can be gathered: Socrates cannot experience death in order to prove that the soul continues after it. The affinity argument is key here as it establishes the differences between the body and soul and so supports his final argument, but it is later in the dialogue that Socrates’ final attempt to prove that the soul is immune death and destruction comes.

Socrates supports the affinity argument using logical rather than empirical proof, namely by comparing the soul to the Forms in order to show that it is everlasting, and demonstrating how the body is different and will therefore decay. First, he argues that ‘things that always remain the same and in the same state are most likely not to be composite, whereas those that vary from one time to another and are never the same are likely to be composite’, making a more explicit link to the soul in saying that ‘these that always remain the same can be grasped only by the reasoning power of the mind and are invisible’ which implies that the soul is non-composite - as Socrates believed. Many philosophers, on the other hand, disagree and see the soul as composed of desires such as appetite and lust, and although Socrates maintains that these are part of the body and the soul is consequently free of them in death, his argument is weakened by the fact that he presents no evidence for the soul being non-composite, but simply links it to other non-composite entities. In contrasting the soul with the body - ‘The soul resembles the divine, and the body resembles the mortal’ - which we recognise as subject to decay, he supports his argument that the soul, conversely, is not. He himself makes this conclusion within the text: ‘Is it not natural for the body to dissolve easily, and for the soul to be altogether indissoluble, or nearly so?’. Therefore, using logical rather than empirical proof, Socrates substantiates his belief that the soul is immune to destruction, and he later uses this argument in his final attempt to prove its immunity both this and death.

Having differentiated the body and the soul, later in the text Socrates goes on to state why the latter, unlike the former, is ‘deathless’ (105e)1. He uses the example of snow and the hot to do so, saying ‘that being snow it will not admit the hot […] but when the hot approaches it will either retreat before it or be destroyed’, and the supports this by arguing that its oddness is an essential property of the number three: ‘Shall we not say that three will perish or undergo anything before, while remaining three, becoming even?’. As a result, if its oddness were taken away, it would no longer be three. Having ‘quite sufficiently’ established this, Socrates uses the same argument in terms of the soul in order to prove that it is immune to death, asking ‘What is it that, present in a body, makes it living?’ and receiving the answer ‘a soul’. From this, he draws the conclusion that ‘whatever the soul occupies it always brings life to it’, and therefore must be ‘deathless’ because ‘the opposite Form to the Form that achieves this result could never come to it’: the soul being that which grants a body life means that it cannot have any part in death. In this way, Socrates successfully uses logical proofs in his final attempt to prove that the soul is immune to death, simultaneously demonstrating their advantages over empirical science as he is able to create sound arguments about invisible and intangible objects, which cannot be done when using empirical methods.

However, his argument that the soul is immune to death does not prove that it is equally immune to destruction, and so Socrates must present another to achieve this. In the affinity argument, he attempts to do so by likening the soul to the Forms, which are indestructible, but therein fails to support his claim that the soul is non-composite - although he does importantly show how the soul is different from the body. He is therefore able to use its similarity to the Forms and difference to the body to demonstrate its immunity to destruction after having shown it to be immune to death. Firstly, he uses the two examples of snow and the number three to show that the Forms are a priori indestructible, and so that that which admits the Forms is also indestructible: ‘If the uneven were of necessity indestructible, surely three would be indestructible?’; ‘If the non-hot were of necessity indestructible, then whenever anyone brought heat to snow, the snow would retreat safe and unthawed’. Consequently, ‘if the deathless is also indestructible, it is impossible for the soul to be destroyed when death comes upon it’, unlike the body which can evidently decay - as Socrates also states because ‘when death comes to man, the mortal part of him dies […] but his deathless part goes away safe indestructible, yielding the place to death’ (106e)1. Here, Socrates almost combines empirical and logical proof as he uses the former when discussing the body’s decay, and the latter in terms of the soul’s indestructibility, and so in his final attempt to prove that the soul is immune to destruction, his reliance on logic does outweigh empirical science, but to an extent he employs both.

In conclusion, Socrates successfully managed to present the advantages of logical and a priori proof over empirical science in his final attempt to prove that the soul is immune to death and destruction because in most cases he is unable to gather empirical evidence. Only the body’s decay after death can be experienced; the soul’s continuation after death and the Forms are impossible for humankind to gain knowledge of empirically, and so any argument must take a basis in logical and a priori proofs - as Socrates’ final argument does. Therein, he uses logic to draw the conclusion that as the soul brings life to a body it will not admit death, and just as the deathless cannot be destroyed neither can the soul when the body is subject to death, and therefore, the soul is immune to both death and destruction.