Forms come by nature. Thomas says, “certain seeds of the sciences pre-exist in us, namely, the first conceptions of the intellect which are known right away by the light of the agent intellect through species abstracted from sensible things” (Thomas Aquinas: Selected Writings, Penguin Books., London 1998, p.198). The pre-existent seeds Thomas is referring to are those images which we passively receive by our senses and naturally actively abstract to some degree by way of our inherent agent intellect. Our agent intellect is created to function commensurately with our senses as it interacts with nature. The agent intellect is the active principle in our intellect that abstracts, or processes, all our sensory data, rendering them to our memories (passive intellect) for further consideration (if we want).
For an excellent introductory guide to Aquinas follow this link.
In other words, nature, on its own, cannot place the forms (the abstractions) within us. The forms exist in nature, in relation to us through our senses, as passive principles. If I understand this correctly, both our senses and the forms in nature are passive and are linked to one another somehow – divine light perhaps, or the general coherence of creation (?). The forms which exist passively in nature require our active agent intellect to ‘actualize’ them and render them to the passive principle in our intellects (potential intellect – memory). All of nature in large and small ways is a continual interaction between active and passive principles. In a human, the first of these abstractions are ‘universal principles’ which, as our reason develops and if we are inclined, lead to ‘the actual knowing of particulars’. In other words, from the moment a newborn baby abstracts and understands (in a limited way) forms of his/her mother (vision, smell, sound) to be associated with relief of hunger to when an astrophysicist contemplates extraordinary mathematics to explain aspects of nature on a cosmic scale, we are operating in accordance with our natures in relation to nature. This active principle processing received phantasms has to start in some way the moment we start receiving phantasms in order to avoid some arbitrary moment in which God zaps us and gives us our agent intellects (or turns it on). Anyway… Typical human cognitive function is that our senses passively receive, our active intellects abstract, our potential intellect receives, we actively contemplate our memories and so on – and from day one we slowly grow in knowledge). We are created to live and interact with nature in this way, and in this way, the forms ‘come from nature’. We are not merely passive agents receiving sensory data. We process the data using our inbuilt active principle. Otherwise, as Thomas says, “man could not acquire science on his own” (p. 199). The action would all be external to us, and we would be only passive recipients.
Healing comes from nature. The natural healing of a human body is not the same sort of interaction of active and passive principles that exist between our intellect, our senses and the various forms of nature. The interaction of active and passive is integrated within our bodies so as to be “complete active potency” (p. 199). The “intrinsic principle” is sufficient within us to bring about the “perfect act” of healing – there is an active principle of healing within us which interacts with the passive principle of our matter, restoring it to health from sickness. The physician only aids the preexistent “active potency” within us. The physician only augments and supports what our natural bodies are already inclined to do in healing (“aided by medicine,” p. 199). The physician is not an external active principle to his/her patients and the patients are not a passive principle to the physician in terms of the process of healing (though in other ways the principles of active and passive exist within human relationships as well – for example as between parent and child or teacher and student in the process of learning).
Knowledge from God is by way of ‘teaching within’. Whereas we are able to abstract forms from nature received by our senses, and to grow in understanding as our reason is trained, we cannot claim that our reason and its tools (the active and passive principles which comprise our reason and our senses which receive the phantasms) are self-originating. They are given to us by God. Furthermore, they are not merely placed in us by God, but God himself is the “complete active potency” at the heart of nature, and thus also at the core of human existence. Thomas says, “it is God alone who teaches within and principally, just as nature principally and within heals” (p. 200). In this sense, the “complete active potency” of our bodies in healing themselves needs to direct our hearts and minds towards the consideration of the ultimate reality of God sustaining and ordering the whole of creation. “The light of reason by which principles of this kind are known [i.e., self-evident principles and those things which necessarily follow on from them leading towards increased knowledge] is placed in us by God, bringing about in us a kind of likeness of uncreated truth” (p. 200). As we use our God-given reason in a proper way increasingly to understand the world in which we live, God “brings about in us” an increased “likeness of uncreated truth” (i.e., Divine knowledge). As we have seen, it requires faith to move beyond the merely material into the realms of “uncreated truth”, as we continue to be taught by God (but also other people and angels who know what we do not). All this being said, though God is the originator and sustainer of our reason and material existence, he gifts it to us so that it is also in a true sense “ours.” In other words, I believe Thomas is saying they are fully ours, but contingent upon God’s causality, sustenance etc. So, fully ours in terms of our integrity of being, yet not equal to those elements inherent in the originating Cause in which we participate and upon which we depend.
Mind your Maker 