In Chapter 7, I focus on the ‘conventionalist threat’ against the account presented in this book. I present Warren’s conventionalist account of mathematics and discuss Wittgenstein’s philosophy of mathematics and its debated conventionalism. I identify strict conventionalism according to which mathematical truths are fundamentally arbitrary as the main threat against the present account. I then show that, due to arithmetic’s foundations in the evolutionarily developed proto-arithmetical abilities, my account survives the conventionalist threat. Arithmetical knowledge, under the present understanding, is maximally inter-subjective, which is enough to deal with the threat of arbitrariness. I then discuss the nature of mathematical conventions further, pointing out their importance without succumbing to the view that arithmetic is fundamentally based only on conventions.

In order to analyze the relationship between international, EU and national law properly, this chapter establishes a working hypothesis: a common denominator of international, EU and national law. Analogous to the historical idea of social contract theory, this common denominator is consensus. After revisiting the major criticism of consent as a (moral) obligation to obey the law, the chapter elaborates on the moral duty to adhere to the pacta sunt servanda principle. After discussing the thesis of an innate Universal Moral Grammar (UMG) that relies on an analogy to the thesis of a universal grammar of the human faculty of language in linguistics, this chapter submits that Colwyn Trevarthen’s concept of primary, secondary and tertiary intersubjectivity is more suitable for conceptualizing the origins and development of the biological setup of human morality. This chapter refers to intersubjectivity, as the decisive concept to align morality and its development with core concepts of (developmental) psychology in order to lay bare the origins of moral normativity, which is essential for us as a basis for the pacta sunt servanda principle.

It is only in the last few years that some factors, such as the spread of eating disorders, closely related to bodily experience, have prompted researchers to a greater systematization of theory: in summary it is a scientific process which has led to the inclusion of all the perceptual, affective, and cognitive representations of the human body in two basic, intertwining concepts: body schema and body image. The body image is also generated and reorganized because of external stimuli. This process takes place on various levels: emotional, imaginary, sensory, and creative. The analysis of body image is therefore not a neurological issue, but a psychological one. In recent decades, scientific research has attached increasing importance to the interactive and relational components of the subject's psychological experience: it is not only intimate relationships that can affect human perceptions but also the wider social environment, such as the mass media, which reinforce beauty ideals or elicit changes in the way people perceive their own appearance and influence perceived norms.