Adversaries to the proposal in this chapter about Materialism are of two kinds.⁴ Some Materialists say the vital principle is the material body. Other Materialists admit some vital principle, distinct from the structure of the organism and from the physico-chemical forces of raw material, and this vital principle is actually superior to the material; nevertheless, this vital principle is not something substantial but a mere accident, inherent in common matter.

Materialists who conceive of the vital principle as just the material body are Francis Bacon (1561-1626), Pierre Gassendi (1592-1655), and many Mechanicists. Among the moderns there are those who hold the vital principle to some kind of imponderable fluid, nervous energy, magnetic force, or electromagnetic force.⁵ "It has been said that during the 1960s (and since), Materialism became one of the few orthodoxies of American academic philosophy, and analytic philosophy elsewhere has shown a similar tendency," notes Mautner.⁶

Materialists, who admit some superior vital principle not as something substantial but a mere accident, inherent in common matter, are those who do not distinguish between living corporal substance and non-living corporal substance. The substance is not the vital principle, but the accident inhering in common matter. Authors of this kind are: Haller, Wolff, Blumenbach, Treviranus, Ioannes Müller, Liebig, Bonnet, Needham, and Maupertius. Among the more modern authors are those who explain life by referring to diverse entities and hypothetical forces which direct and perfect the vital process.⁷ However, some of these moderns write without philosophic precision, so that interpretation of their thought is sometimes doubtful; even the term Materialism is referred to as Physicalism, which has at least two meanings.⁸

Relative to our theme of evolution,⁹ some forms of derived Positivism expressly turn to and evolve a metaphysical character really contained in their professed principles, and they produce explanations that are metaphysical (even if Materialist) relative to phenomena: Charles Darwin (1809-1882),¹⁰ Herbert Spencer (1820-1903) and his ontological synthesis of the "universal law of evolution"¹¹ and Karl Marx (1810-1883).¹²

Favoring the thesis would be all Neo-Scholastics, who would hold it as common doctrine with all the Aristotelian¹³ and Scholastic philosophers. Palmes¹⁴ is a example of the Neo-Scholastic affirmation of the inadequacy of Materialism in the explanation of life. Gredt, however, believed that extending evolution to man was Materialism.¹⁵

Adversaries who reject the proposal make it clear that the thesis proposed is a serious subject for discussion. The thesis proposed and defended as true presents an objective problem worthy of dialogue.

Adversaries who seriously contradict the proposal in this chapter deserve respect. These adversaries have reasons for their position. In every false position there is some truth. In dialogue, every attempt should be made to clarify that truth. In this case, the Materialist begins his philosophy by observation of the visible, physical and material world, where the Neo-Scholastic also begins, and then Neo-Scholastic continues the investigation; matter, according to common signification, is the same as extended body.¹⁶ Accordingly, even if our proposal and its proofs demonstrate the adversaries wrong, the reasoning Materialists can be understood and respected.