Hume on Impressions and Causation
According to David Hume’s proposition, all ideas can be related among each other through the principles of resemblance, identity, relation in space and time, quantity, contrariety, and causation.1 These are the principles established by Hume which form the principle of connexion among ideas and impressions. The relation between ideas and impressions is also very important, it is this conjunction of terms that forms the most immediate and reflective impression of reality. More complex ideas are built on top of simpler impressions — complex ideas are derived from simple impressions which correspond to the exact representations of the occurrence that they represent.2 These perceptions along with the principles of connexion, form the foundation on which a relation between an idea and another is possible.
An impression constitutes the closest resemblance to its inherit idea but is not always the idea itself. An impression relies on some mode of sensing that frequently entails a particular way of translating the original occurrence or idea into an impression or a memory. These impressions serve as a foundation to all deducible ideas which are products of the reflexion.3 This can be explained through the fact that whenever one losses the ability to perceive an effect of a particular occurrence, he would no longer be able to determine its cause, regardless of the extent of his/her mode of reflexion. Hume constantly reminds the fact that the relation among ideas, relies entirely on the rule where the cause always precedes the effect — is is a subtle reminder that considering ideas that imply otherwise — would be an activity that would not be founded on the universe’s law of causality. When one loses a particular sense of perception, he/she would also cease to sense anything associated with that particular mode of perception since he/she will no longer have the means to produce the effect that would cause the perception. As Hume states, “our impressions are the causes of ideas, not our ideas of our impressions”.4 If there are no modes of perception that allow one to perceive an idea, then an impression based on that idea cannot be derived.
As Hume proves, it is impossible for ideas to exist before their corespondent impressions, since an impression must always precede the idea that it represents. This is a general tendency of causation which is based on the cause always preceding the effect. Although the ability to conceive ideas that defy the rule of causality, might not entirely seem impossible. Such an an example includes the ideas of a perfect triangle, whose cause cannot be pinpointed within the physical world, but only within the world of ideas. But even imagination however, is not always be a complete substitute to the ability to perceive an impression.5 The more complex impressions are, the more relations they have to simpler impressions and ideas. For example, the idea of passion and desire are not innate and are possible only through the observation of previous experiences.6 It is the hierarchal positioning and ordering of causations that form more intricate ideas such as passion, which might appear as a very typical subjective feeling, but it nevertheless relies on thousands of other past impressions and ideas — all founded on the universe’s rule of causality.
Since the rule of causality constitutes the relations among numerous causations, there seems to be a rule of measure one which all the causations can be placed. Such a rule of measure is referred to as space, and most particularly — time. Time, among all the other principles of resemblances, has an underlying role in ordering these causations along a rule that allows the ordering of causations, which ultimately, constitute all ideas and perceptions. Time however, seems to not always be an underlying principle that constitutes the causation of ideas. In other words, it seems to be an effect of causation, not a cause for causation. Hume also appears to emphasize more on the importance of other principles of causation among ideas, such as resemblance, quantity, and contrariety. Time, although is a part of these principles of causation, can also seem be a derivation based on these principles. The task to investigate whether time is a cause or an effect therefore prevails.
The Irreversibility of Time
In the previous relations, it was assumed that time is one of Hume’s principles of connexion among ideas. But what are the inherit qualities of time, and is it always a foundational rule of measure along which ideas are placed and ascribed? Hume affirms that time is a quality without which, ideas cannot be related to each other, or would otherwise be related in completely arbitrary ways. The idea of time should have also come from somewhere, since the idea of time would not exist if it had not a cause, which further proves the possibility of it not being a foundational rule of measure. It remains important to investigate whether time is a foundation of measure, or if it can be attributed to something less inherit — a pure product of causation.
It is when comparing or discerning two objects from one another, do the principles of causality become one of the most, if not only, determining factors that underly the relations among ideas. But from where do these ideas originate and how do they gain the quality of being comparable to each other? How can ideas initiate when an effect cannot exist without a cause? What is the origin of these ideas and what is the extent of their influence on time? Could time no longer be an existing principle when it no longer has any idea to act upon?
To illustrate that time is a product of causation and not a fundamental measure for relation among ideas, it would be helpful to illustrate what it would hypothetically be like if time where to be reversed. Reversing time however, seems to be unnecessary, since whatever direction it gets reversed, the rule of a cause preceding the effect _— will always prevail. This signifies that even if time where to be reversed, the _cause will nevertheless continue preceding the effect. What will result is not a world of reverse causation where everything is played backwards, but a regular world where the changes in the flow of time are hardly noticed. Which would illustrate that time is not a fundamental measure of relations among ideas but a cause of causation.
To illustrate this nature of time, it would be helpful to illustrate an ability that allows one to move mountains and re-direct rivers to flow towards their opposite directions. Given such powers, even if one redirects a river in such a manner, it would in no way alter the inherent tendency of water to flow from top to bottom. Just like reversing the flow of water, reversing the direction of time, would in no particular way effect the rule of cause and effect — just like reversing a river’s direction would in no way effect the water’s tendency to flow from top towards the bottom. Time is just like water in a river, it’s inherit tendencies remain, regardless of how extensively its form, shape, or direction is altered. But this relation illustrates that time is not just a foundational principle, but rather, a product based on the presence of other principles of causation. Like water, time does not have it’s own strictly determined direction, it flows based on the presence of other circumstances that determine whether it flows, or stays still. The only reason why it appears that time has strictly determined direction, is because we have not found a way to get out of the flowing river of time — a position similar to that of tadpoles.
If time is not one of the primary measures of causation, would it then cease to exist if there where no objects and ideas on which it can act? Perhaps if one imagines an empty realm, that contains no ideas nor objects which can be related to each other. Such a space would not contain any of the principles of connexion since there would be no ideas to relate to other ideas. But time seems to be in need of ideas and objects in order to flow — just like water needs a river, hills, and plains, since otherwise, water would remain still. Even if this realm is voided from ideas just in a particular spot, there would be either none, or a lacking circumstance for time to exist. When there are no objects nor ideas on which time can act, so it seems, time no longer has a cause to exists. Time therefore becomes an effect that cannot exist without its cause, which further illustrates that it might not be a foundational rule of measure.
It also seems that there is no cause, nor effect, nor causation in a place that is deprived from ideas and objects of impression. Without a subject to perceive ideas, or even without the ideas themselves, time would not have a context in which it continues to be relevant. Whenever there is an absence of ideas, there is also an absence of time. Time therefore remains dependent on other principles of causation and is rather relational as apposed to being something universal.