The difference between transitive and reflexive action is not an accidental difference of _degree_, but an essential difference of _kind_. In reflexive actions, the source of the action and the recipient of the effect or modification produced by it are one and the same substantial unit or being. In transitive actions, the receptive subject of the positive change is an alien unit distinct from the unit, which puts forth the action. Hence a reflexive action is not an action which is _less_ transitive; it is an action which is _not at all_ transitive, but intransitive. The difference, therefore, between the living organism, which is capable of both reflexive and transitive action, and the inorganic unit, which is only capable of transitive action, is _radical_ and _essential_. This being the case, an evolutionary transition from an inert multimolecule to a reflexively-operating cell or cytode, becomes inconceivable. Evolution might, at the very most, bring about intensifications and combinations of the transitive agencies of the physicochemical world, but never the _volte face_, which would be necessary to reverse the centrifugal orientation of forces characteristic of the inorganic unit into the centripetal orientation of forces which makes the living unit capable of self-perfective action, self-regulation, and self-renewal. The idea, therefore, of a spontaneous derivation of living units from lifeless colloidal multimolecules must be rejected, not merely because it finds no support in the facts of experience, but also because it is excluded by aprioristic considerations. § 8. An Inevitable Corollary But, if inorganic matter is impotent to vitalize itself by means of its native physicochemical forces, the inevitable alternative is that the initial production of organisms from inorganic matter was due to the action of some supermaterial agency. Certain scientists, like Henderson of Harvard, while admitting the incredibility of abiogenesis, prefer to avoid open conflict with mechanism and materialism by declaring their neutrality. “But while biophysicists like Professor Schäfer,” says Henderson, “follow Spencer in assuming a gradual evolution of the organic from the inorganic, biochemists are more than ever unable to perceive how such a process is possible, and without taking any final stand prefer to let the riddle rest.” (“Fitness of the Environment,” p. 310, footnote.) Not to take a decisive stand on this question, however, is tantamount to making a compromise with what is illogical and unscientific; for both logic and the inductive trend of biological facts are arrayed against the hypothesis of spontaneous generation.