One of the main problems of the soul theory is how the soul, which has no material properties, interacts with body. Because it is difficult to understand how an immaterial being interacts with matter. In particular, as our scientific understanding of the way the brain works and how it affects our psychology expands, the question of whether a soul is needed for the mind manifests itself more strongly. In this context, current data on the close connection between the brain and (...) the mind is often used as an objection to the understanding of the soul. One of the recent data that has been claimed to have dealt a heavy blow against the understanding of the soul is the split-brain case. The split-brain case is the name given to the condition of patients whose brain hemispheres are surgically separated from each other. The difference of this case from other cases used against dualism is that it pointed out that the integrity of consciousness also depends on the brain. Because although there was a connection between many mental functions and the brain before, it was not between the unity of consciousness. For it was a new claim that the unity of consciousness also depends on the brain. On the contrary, arguments were used in favor of the existence of the soul, stating that the brain cannot provide the unity of consciousness due to its multi-part structure, and therefore an indivisible soul is necessary. Whereas, in the split-brain case, patients whose brain hemispheres were separated from each other could think and act like two different people. This is interpreted as contrary to the soul view, which argues that the individual and the soul are indivisible. The present study considers whether the split-brain case does indeed offer a strong argument against dualism. In this paper, first of all, more detailed information about the split-brain case will be given. Then, the arguments of those who use this case against dualism and why the issue seems problematic in terms of the soul view will be discussed. Afterwards, some solutions offered by dualists to this problem will be evaluated. There are three different strategies that dualists follow at this point. The first one rejects the idea that consciousness is divided as a result of the split-brain phenomenon, the second rejects the idea that the soul is indivisible, and the third way accepts both, but argues that they are not contradictory, because a single soul can have a divided consciousness. This paper argues that even if it is accepted that more than one stream of consciousness emerges as a result of the split-brain case, this cannot be seen as a finishing blow to dualism. Despite this, the case in question can be regarded as a strong argument against dualism. For a counter-argument to be strong, it does not need to conclusively demonstrate the falsity of what it opposes. It suffices to show the weakness of its probability of being true. In this respect, the split-brain case greatly weakens the probability of dualism being true. (shrink)

Today, when it comes to soul-body dualism, the view that comes to mind is the substance dualism that Descartes systematized. As the name suggests, this dualism implies that there are two different types of substances. Similarly, although Ibn Sīnā also adopted a kind of substance dualism by stating that the soul is a different type of substance than matter, his dualism differs from Descartes’ in important aspects. It can be said that the most important reason for this difference is that (...) both ideas belong to different traditions. While Ibn Sīnā’s dualism carries the traces of Aristotelian hylomorphism, Cartesian thought is built on the post-Newtonian understanding of the mechanical universe. This significant difference has deeply affected soul-body conception of both philosophers. The aim of this study is to reveal the fundamental differences between the dualistic understandings of these philosophers in the context of soul-body. Thus, it will become clearer where the Avicennian dualism stands in terms of contemporary philosophy of mind. In this context, the first question to be addressed here is whether, according to both philosophers, the immaterial part of man means the same thing. The answer to this question is negative. The functions that Ibn Sīnā and Descartes attribute to the immaterial substance are quite different from each other. According to Descartes, it can be said that the soul is actually identical with the mind. Because, he describes the soul as the substance whose essence is to think. Here, Descartes is not only referring to theoretical calculations by thinking. It also includes phenomenal consciousness, that is, conscious phenomena, which is also called qualia in contemporary philosophy of mind. Thus, according to the Cartesian tradition, the fundamental distinction between soul/mind (the immaterial substance) and body is phenomenal consciousness: A thing is a soul only if it can have phenomenal consciousness. Whereas, Ibn Sīnā does not see phenomenal consciousness, which is the most basic function that the present Cartesian dualist tradition attributes to the soul, as the basic function of the immaterial substance. In fact, he does not even see it as a function of the human nafs. In other words, according to him, the main function of the human nafs is not to feel/experience or to have phenomenal consciousness. Such functions can also be performed by animals that do not have an immaterial substance. According to Ibn Sīnā, the main functions of the human soul are theoretical or universal thinking and being self-conscious. One of the places where this distinction can be seen most clearly is their thoughts about animal souls. Both philosophers argue that animals do not have an immaterial substance in addition to their material bodies. However, while this means that animals are unconscious automatons for one philosopher (Descartes), it does not mean anything like that for the other. Because, according to Avicenna, an immaterial substance is not necessary to have consciousness or feeling. However, according to Descartes, for a being to be conscious or sentient requires it to have an immaterial substance. Since animals do not have such (substantial) souls, Descartes saw them as unconscious robots. Another point where the same difference can be observed is an argument put forward by Avicenna to prove this immaterial substance, which he addresses as the human soul. According to Avicenna’s argument, the existence of an immaterial substance is necessary for man’s access to universal knowledge, not for having consciousness. However, according to the argument used in the Cartesian tradition and known as the unity of consciousness argument, the existence of immaterial substance is necessary for the unity of consciousness (not knowledge). The aim of this study is to reveal the basic differences between the dualistic understandings of these philosophers in the context of soul and body. In order to reveal these differences, the following points will be discussed: The question of whether animals are conscious and Avicenna’s argument mentioned above. Because the differences in the handling of these two issues by both philosophers will guide us to reveal the fundamental differences in their dualistic understanding. In this study, it will be argued that the dualistic understanding of Avicenna and Descartes in the context of soul-body are radically different from each other, especially over these two issues. (shrink)

Richard Swinburne is one of the most important figures in philosophy of religion who took special interest in the soul. Also he is one of the most prominent defenders of dualism –also known as mind-body dualism or substance dualism– that regards humans as composed of two different substances called body and the soul. He defended the dualist view against contemporary problems of dualism and contributed to it with his three books, namely The Evolution of the Soul; Mind, Brain and Free (...) Will and Are We Bodies or Souls? alongside with other publications. In this paper, I will introduce Swinburne’s version of Cartesian dualism and critically investigate whether it provides us some reasons to believe in the soul. For this reason, I will examine the two principle arguments Swinburne offers in the explanations of dualism –one of them is known as the conceivability argument and the other is based on an imaginary scenario from transplants– along with their critics. To sum up, the main point drawn in this paper will be Swinburne’s arguments for dualism along with some of their critics. (shrink)