Chapter 6

The intimate union of spirit and matter

823. The reason why the concept of matter (and indeed that of form of body) does not provide us with the principle of motion is that the concept of matter and of body comes to us from perception, which shows us the act in its term, not in its principle. This term (the felt element) is extended. When this felt extension is relocated, motion is present, but the displacement is not in the term itself which is perceived when already constituted, not before. Prior to perception, it is not term, it is not felt. On the contrary, the action relocating the term by transporting it from one place to another is an action anterior to the constitution of the term (the felt element), and consequently does not fall under perception.

824. We should also consider that the term (the felt element) from which alone we derive the concept of mass, body, matter and even of foreign force (the sole concept of which we have experience) is something that we feel in our spirit, in the sentient principle. This allows us to conclude without doubt that the spirit itself concurs with the sensiferous element to produce this term. In fact, the sentient principle receives the action in its own way, that is, as an active principle. But how does the sentient principle collaborate in this? We have to say that it concurs in everything, that is, in
1. the sensible element and
2. the mode of the sensible element, which is extension. The sentient principle collaborates in producing the sensible element because without a sentient principle there can be no feeling; the sentient principle collaborates in producing the mode of the sensible element, extension (continuum), because extension or continuum can be present only in what is simple.

825. The sensiferous element can only arouse the spirit to produce the felt element with its mode, with extension. This, however, is the transcendent concept of the sensiferous entity, the concept that shows the sensiferous element in its principle, in the corporeal principle. This does indeed help to explain how matter and its concept are generated, but it is not the concept of matter.

826. Note that matter, as given to us by perception (the common or popular concept), is highly involved with what is subjective. We should be careful not to reason about the concept of matter as though it had some truth even outside perception; it is true, but in perception. If we want to know what matter is outside perception, we find that it slips away from us. We are no longer speaking about that which holds the attention of the whole world — the world always speaking of matter as it is perceived. So too, the senses do not delude us if reason recognises in them what they give us and nothing more. If, however, we claim that the senses furnish us with something they were not destined to give us, we immediately fall into error — although it is not the senses, but reason which errs by judging beyond the limits conferred by sensible data.

827. Second, it is very helpful to consider carefully the transcendent concept of matter, or better, the transcendent concept of the entity which corresponds to the common concept of matter. This concept enables us to understand the connection between things in nature and, in our case, between spirit and the corporeal principle. It also helps us to see how several entities(44) are produced from their connection and interaction.
We rightly conceive these entities in isolation, and hence as entia or substances. We say nothing about their nature, but simply affirm that they are 'the first act which we perceive, in which and through which many second acts subsist.' Substance, as we know, is 'the first act that makes other acts subsist.'

828. The word 'substance' does indeed have two meanings. Its transcendent meaning expresses the absolutely first act which makes everything subsist. In this meaning, substance is proper to God alone. Its common meaning expresses 'the first act (in our perception) of the entity we perceive.' In this meaning, relative to us, we distinguish several substances which we can suitably call relative, not absolute, substances. In this sense, matter is substance.

829. Finally, the distinction between the two concepts of matter (the transcendent and relative concepts) is extremely helpful in explaining the origins of the different opinions of philosophers about matter, and reconciling them.

Notes

(44) This is another example of the synthesism in nature of which I have written on several occasions. -Principles of Ethics (PE , ch. 2); Storia comparativa , c. 8, a. 3, §7; AMS , 258-268