Understanding Knowledge Types and Idea Association
Types of Knowledge and Their Characteristics
In the first class – knowledge about relations of ideas – Hume includes all propositions of geometry, algebra, and arithmetic. Statements like “the whole is greater than the parts,” and “the sum of two and two equals four,” say only the relations between ideas (e.g., between the ideas of whole and part, in the first sentence). These propositions can be reached by the simple operation of the spirit, by mere reasoning, without resorting to experience. The truth of these propositions is independent of sampling experience. They constitute, according to Hume, the domain of certain knowledge because the opposite of a proposition of this kind is impossible and implies a contradiction. Therefore, they are necessary truths: what is established for them is well-established and cannot be otherwise, based on the principle of contradiction. They are analytic truths because what is expected of the subject is included in the notion of it and necessarily belongs. They are true explanations because they do not expand our knowledge but make it explicit, and they are true a priori, independent of experience. In the field of logic and mathematics, absolute certainty can be achieved.
Instead, knowledge that refers to facts depends entirely on experience. In statements like “gold is yellow,” one cannot be reached by a simple argument; it is necessary to resort to observation and experience. The truths of fact – the object of study of physics – are synthetic: what is expected of the subject in the proposition is not contained in the notion of it. They are contingent, as what is provided by them may be otherwise; the opposite, as provided by them, involves no contradiction. They are ampliative: the knowledge that we provide is greater than that possessed, and they are “post” because it is established from experience and depends on it. The only thing that guarantees the truth of propositions that assert facts is experience, so that we can only be sure of what is or is present to the senses or registered in memory, but not what transcends these boundaries, because the opposite of each event is always possible and involves no contradiction.
Principles of Association of Ideas
Association of Ideas: The natural layout of the imagination by which our mind tends to relate several ideas. As a result of the association of ideas, the presence in our mind of an idea leads to the emergence of another or others. The ideas or mental contents succeed each other and combine with each other in a certain order and regularity: when our mind has one idea, and we make use of voluntary thought, but let the different mental contents flow spontaneously one after another, this idea will happen to another which is linked or attached. Ideas attract other ideas, in the same way, Hume suggests, that in the physical world one body attracts another thanks to gravity – Newton’s influence.
The laws of this association describe the forces which tend to evoke ideas to others. Since joining forces with other ideas are, as Hume says, “soft power,” the sequence of an idea for another is not a series that has to give an absolutely necessary result, so that the laws describing these regularities are not strict laws. We simply say that if the idea ‘A’ is linked to the idea “B,” and our consciousness has the idea “A,” it is likely that the idea “B” will occur following it. Thanks to these natural connections, complex ideas are spontaneously formed from simple ideas. Laws of the association describe these connections and are the result of imagination, not reason.
It is clear that there is a principle of connection between the different thoughts or ideas of the mind and that, when presented to the memory or imagination, some others introduce a degree of order and regularity. Despite that, I have not found one philosopher who has attempted to enumerate or classify all the principles of partnership. From my point of view, there seem to be only three principles of connection between ideas:
- Resemblance
- Contiguity in time or space
- Cause or effect