Chapter 6

The struggle between life instinct and 'mechanical forces'
does not admit of conciliation

1839. Natural philosophers who have dealt with this question did not recognise the essential difference between the two kinds of struggles I have described. Having looked at the question as a whole without first submitting it to analysis, they came to absolute conclusions. They either denied or affirmed the possibility of conciliation.

1840. I think that the truth is once more to be found between the two opinions. In other words, one part of this struggle is irreconciliable, the other reconciliable. The struggle between vital principle and mechanical forces does not admit the conciliation we are looking for; the other struggle, between vital principle and attractive forces, does not exclude this conciliation.

1841. The ancients never doubted the reality of the struggle which can be seen between the spirit and matter, nor did they ever think that effects which were so obviously contradictory could ever be reduced to the same cause.
This is the opinion that first presents itself to the spirit. In fact, observation presents three classes of highly distinct phenomena with opposite characteristics: 1. phenomena which are purely material and mechanical; 2. physical, chemical phenomena, in a word, phenomena of attraction; 3. animal phenomena. On this basis, humanity as a whole deduced that these three clearly distinct classes of effects had a corresponding number of similar causes or forces of distinct nature which would explain the existence of the effects. In other words, mechanical, attractive and animal forces would be present, each operating according to a different law. The consequence is the inevitable possibility of struggle.

1842. The reasoning of those who deny conciliation is based on observation. For certain modern authors, a real, necessary struggle in nature was repugnant. Again, they were attracted by the beauty and elegance which, it seemed to them, should be possessed by a very simple explanation of natural phenomena. In this explanation, everything would be reduced to unity, to a single cause. This wholly ideal attraction drew quite a number of authors into materialism. They mistakenly thought they could find the cause of every kind of phenomenon in mechanical forces alone, and did not exclude from this explanation even the phenomena of feeling and thought.

Others attempted different ways of arriving at the same conclusion, but always carried along by their imagination. As a result, all those who up to the present have seen the struggle between vital principle and nature as something merely apparent (as though a single, identical agent represented several personages at the same time) have unfortunately abandoned sound, philosophical method and cannot, therefore, take a single, safe step.

1843. The middle opinion which I have spoken about, and which appears to me to be true, comes as a natural corollary from what has been said above about the inertia of matter.
There I showed that no mechanical effects of the communication and conservation of motion can pertain to matter, but must belong to the hidden principle which posits matter in being. This I called the corporeal principle.
I also showed that none of the effects attributed to attraction can pertain to the matter in which they appear, but to the sensitive principle joined to matter.

Then I established that all movements to which matter is subject must be reduced to two spiritual causes, that is, to the corporeal principle and to the sensitive principle.
If, therefore, there are two specifically different causes of motion which, because they are two, obey different laws, it is useless to attempt to remove every possibility of struggle in nature and to draw all movements under a single law, and their origin under a single cause.

However movements, in so far as they obey mechanical laws, must be attributed to the corporeal principle and, in so far as they obey attractive laws, must be attributed to the sensitive principle. It is necessary, therefore, to conclude that the struggle between life instinct and mechanical forces is real. Its possibility cannot be dismissed. On the other hand, the struggle of this instinct with attractive forces is only apparent, that is, they are reciprocally contrary effects of the same principle. These contrary effects depend upon the different portions of matter invested by the life instinct, and the different conditions in which this instinct is found. Thus, following a single law, the instinct produces contrary effects.