Ley natural como ley de la razón práctica
Jensen critica la teoría del conocimiento de la ley natural defendida por Rhonheimer, porque según Jensen, Rhonheimer dice que las inclinaciones no son decisivas en el conocimiento de la ley natural. Lo que el hombre ve razonable hacer eso es la ley natural, en la medida en que la razón lo dicta como razonable, como una evidencia no derivada del conocimiento de las inclinaciones
p. 85
Rhonheimer
What is according to nature, on this reading, is simply whatever practical reason dictates. Why? Because the nature of man is to be rational.
2 l-Il 71 2.. "Sed considerandum est quod natura uniuscuiusque rei potissime est forma secundum quam res speciem sortitur. Homo autem in specie constituitur per animam rationalem. Et ideo id quod est contra ordinem rationis, proprie est contra naturam hominis inquantum est homo ; quod autem est secundum rationem, est secundum naturam hominis inquanmm est homo. »
p. 86 According to Martin Rhonheimer, for instance, "For practical reason to be ‘based on that which is according to nature’ thus means to be "based on principles that are known naturally’’. Nature, in these contexts, does not refer to some biological teleology, but "’nature’ here is something given in and with some natural form of exercise of reason.’"* Indeed, Rhonheimer thinks that those – who refer to natural ends have confused natural law, which is simply the dictates of natural reason, with an account of natural law. Natural law itself does not come from nature (besides the nature of reason); it is self-standing, not needing any natural teleology as a foundation. It is "a cognitive reality inserted in the human soul which unfolds precisely through the first and spontaneous judgments of practical reason itself.
Perhaps the most telling text explicitly distinguishes between what is according to reason and what is according to nature. (Por eso se apoya en este pasaje de Santo Tomás):
ST: II-II, 154, II, There is a determinate species of lust where there occurs a special character of deformity making the sexual act unsuitable, which can happen in two ways. In one way, because it is repugnant to right reason, which is common to all sins of lust; in another way because, beyond this, it is repugnant to the very order of the nature of the sexual act fitting to the human species, which is then called a sin against nature.
(Pero en cambio, en el comentario a las Sentencias fundamenta la ley natural en las inclinaciones).
p. 97 nota 36 Sent IV, 33, I, The natural law is nothing other than a conception naturally impressed upon men by which they are directed to act appropriately in their own action either as they apply to the nature of the genus, for example to reproduce, to eat, and things of this sort, or as they apply to the nature of the human species, for example, to reason and such things. Every performance of an action unsuitable to the end that nature intends in some activity is said to be against the natural law
107
We have every reason to suppose, then, that Aquinas presents us with multiple examples of an epistemological dependence, moving from a natural inclination, or an intention of nature, to practical knowledge. Of course, the dependence is also ontological. Aquinas does not make the distinction between the two. He has no need to, since the dependence moves in the same direction both for our knowledge and for the reality in things.