ARC research project 2013-2018
Free Will and Causality
The aim of this project is to better understand the relationship between causality and free will. The possibility of free will will be studied starting from the hypothesis of a link between language and neural plasticity. A comparative conceptual analysis of causality in physics and neurosciences will be developed.
From the philosophical point of view, the study of the concept of causality started with Aristotle (384 BC – 322 BC) who proposed four different types of causes (material, formal, efficient, final; Physics II and Metaphysics V 2). During the following centuries, the concept of causality has continued to be interpreted in Aristotelian terms. David Hume initiated the modern approach of causality. He recognized the importance of causal beliefs for human understanding. However, he convincingly demonstrated that causality itself is not observable. Describing colliding objects, David Hume wrote: ‘‘When we consider these objects with the utmost attention, we find only that the one body approaches the other; and the motion of it precedes that of the other without any sensible interval’’ (D. Hume, 1739). The argument of David Hume seems logically impossible to contradict: a necessary connection between events cannot be observed or measured. Only contiguity and succession can be observed. Causality seems indispensable to human understanding but could not be founded rationally and causal inferences are made on the basis of non-causal co-variations. If we follow David Hume’s philosophy, the mind is a white sheet of paper and only learned associations can form the base of human knowledge. Immanuel Kant considered Hume’s conception of causality as deeply unsatisfactory. In Kant’s approach, causality is an a priori category of understanding, a logical necessity for the possibility of experience. Categories of understanding are a priori features of the mind. Therefore, for Immanuel Kant, the mind is not a white sheet of paper. The British philosopher Bertrand Russell tried to clause the debate by declaring the concept of causality obsolete: “The law of causality, I believe, like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm” (B. Russell, 1912). However, we suggest that simply giving up the concept of causation at the macroscopic level is unsatisfactory. More specifically, the concept of causation is central to the notion of free will. Indeed, free decisions could cause behavior if humans enjoy free will and this question is central in modern philosophy.
From a historical point view, the question of free will became central after the 17th century, in relation with the rapid development of modern sciences. Two main philosophers from that period are still central in the contemporary debates.
The 17th century was deeply influenced by ideas developed by Newton and Galileo. In this context, Spinoza considered that humans are inside a completely deterministic world and that human behavior is also completely determined. However, in spite of being completely determined human behavior is not predictable. Indeed, the determination of the causes of behavior is too complex and therefore it is impossible to apprehend all of them. We have to presuppose freedom, which is a manner to recognize that we can never completely know all the determinants of behavior. Consequently, human behavior is not predictable. We have to act as if free will existed but knowing that it doesn’t. To be free is to become conscious of our determinations. In this context, freedom must be distinguished from free will. In Spinoza’s deterministic world, free will is illusory.
For Kant, to demonstrate that free will is possible is not to demonstrate that free will does exist. In the Third Antinomy of Pure Reason (1783), which is precisely linked to the question of causality, Immanuel Kant defends the idea that it is not possible to demonstrate the existence of free will. Both the thesis, that affirms the existence of freedom, and the antithesis, which affirms that there is a complete causal continuity, conduct to a non-understandable world. Indeed, the thesis conducts to a chaotic world, completely inaccessible to reason. The antithesis conducts to a regression ad infinitum logically inacceptable. For Kant, reason is confronted with an undecidable proposition. We cannot demonstrate either that freedom exists or that freedom does not exist. However, Kant asserts that free will exists as a presupposition of Practical Reason. For Kant, we can’t know that free will exists – Pure Theoretical Reason can’t solve this question - but we can postulate that free will exists – Pure Practical Reason presupposes free will. Not only do we have to act as if we were free but for Kant we can postulate that we are effectively free.
In this project, we will adopt this Kantian position and confront it to contemporary conceptions of causality and free will. The concept of free will will be questioned both in philosophical and in neuroscientific terms. The central role of language in relation with neural plasticity will be emphasized and we will propose a new hypothesis to understand free will.