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The Sun Will Rise Tommorow: Causality and Objective Knowledge


All men desire to know. One of such desires include the knowledge of the nature of reality so as to be able to interact with it. The quest to know which stimulated the first known philosopher to account for reality amidst the diversity of things around him also accounts for the various interventions by various philosophers down the ages. In these attempt of theirs to understand reality, they all attempted to explain reality starting with the cause of reality. This brought about the idea of causal relations to the understanding of the nature of reality. Formulating a causal relationship between the subject and the object of knowledge, they opined that objective knowledge is possible. However, causality is seen a psychological habit of connecting two events that we call cause and effect based on induction. Induction for philosophers is also a psychological way of arriving at claims of knowledge which is said to be a probable knowledge, as opposed to deduction which follows logical sequence. Thus, all knowledge based on causality is not objective knowledge and can be refuted in the future. We sleep every night and believe that the sun will rise tomorrow. It is possible that one day the sun will not rise? The sun will rise tomorrow; is it justifiable on psychological basis or on rational basis?


Etymologically, the term “causality” can be traced to the Latin word “causalitas” or “causa” which means “cause”. Causality is the agency of a cause; the action or power of a cause in producing an effect. Epistemologically, we understand by a cause, anything which has an influence of any sort on the being or the happening of something else. A cause is thought of as that which produces something and in terms of which that which is produced can be explained. That which is caused might be either some new substance or simply a change in something that already exists.

In the field of science, scientists set in the laboratory to discover the cause of a thing, for example, to know whether a high intake of alcohol causes humans to develop cancer of the lungs. Informally, physicists use the concept of cause and effect in the same everyday fashion as most other people do. Hence, in the context of physical theory itself for example, some physicists say that forces cause motions. Furthermore, among the psychologists, the concept takes an empirical approach. This is revealed in their investigation of how people and animals detect or infer causation from sensory information, prior experience, and innate knowledge. Thus, Simon Blackburn opines that causation is the relation between two events, such that when one occurs, it produces, brings forth, determines, or necessitates the second; equally we say that once the first has happened the second must happen or that the second follows on from the first.



All objects of the mind are perceptions and perceptions are the objects of human knowledge. Therefore, knowledge starts with perceptions. All our knowledge claims comes from experience and no one knows unless informed by his experience. The perceptions of the mind are impressions and ideas. Impression, comes from the physical world around us, it is vivid, forceful on human mind as a product of immediate experience. Idea, on the other hand, comes from our reflection and is a pale and lifeless copy of direct impression. The belief in the continuity of reality is based on the capacity to reproduce experienced impressions and to create a world of representation. For example, the background colour of the television screen which I look at is an impression, while my memory of it is an idea. This general proposition has become known as the copy principle.

The difference between impression and ideas is of degree in vividness and force. The above implies that, sensations, perceptions, feelings, and so on, fall within the categories of impressions described as more “forcible and lively” upon the mind than those we consider when we are conscious and when we reflect on the thought of them. Ideas, on the other hand, are less forcible and lively than impressions because, they are objects of the mind and not direct impression. It suffices to say, therefore, that no ideas can be formed in the mind without having the impression of it. In this way, the movement from the idea of the object to the object itself requires the validity of causality.


Objectivity of human knowledge is not possible with reliance on causal relations. Possible knowledge can only be acquired through observation or experience. Sense impression is the only original source of all human knowledge, and anything which does not appeal to the senses or of sense datum should be cast into flame. Although human knowledge begins with experience, we cannot arrive at certainty of human knowledge because the foundation of experience as a source of knowledge, which is causality, is unjustifiable.

Causality is subjective. It is subjective because it cannot be verified. Things that we know are objects that are believed to be connected and are always contiguous in time and space. For instance, an object whose cause is always prior to the effect, and objects that have been constantly associated. We hastily affirm that an effect is a result of a cause, which is a constant conjunction with the effect. In other words, in order for X to be the cause of Y, X and Y must exist adjacent to each other in space and time; X must precede Y, and X and Y must invariably exist together.

For instance, our observance that thunder follows lightening makes us associate both together and conclude that lightening causes thunder even though we do not see lightning actually causing thunder. Every time I have drawn near the stove, I have felt warm. This realization, experienced in the past, of having observed one phenomenon constantly united with another, gives rise to the habit of my expecting also in the future a repetition of what has happened in the past, so that, having placed the first condition, I have a trusting expectancy of the second: every time I approach the stove, from force of habit I expect to warm myself. Force of habit gives to the constancy of the phenomenon experienced in the past the force of metaphysical necessity, and from it results the concept of substance, of the laws which govern such substances.

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Relations of ideas are truths that are deducible from other propositions, intuited, and completely dependent on the ideas related. Examples are the sciences of Geometry, Algebra, and Arithmetic; and, every affirmation which is either intuitively or demonstratively certain. That the square of a hypotenuse is equal to the square of the two sides is a proposition which expresses a relation between these two figures. Three fundamental ideas can be deduced from relations of ideas: first, it is intuitively and demonstratively certain because it has no external referent, for example, 1+1 = 2 and a triangle has three sides. Second, its denial will necessarily lead to self-contradiction. Third, it is discoverable by thought alone, meaning that it is a priori. Relations of ideas are beliefs grounded wholly on associations formed within the mind.

Matters of fact on the other hand are truths that correspond to a direct sense experience which can be changed without changing the ideas. Matters of Fact, which are the second objects of human reason, are not ascertained in the same manner, nor is our evidence of their truth, however great, is of a like nature with the foregoing. The contrary of every matters of fact is still possible; because it can never imply a contradiction, and is conceived by the mind with the same facility and distinctness, as if ever so confirmable to reality. That the sun will not rise tomorrow is no less intelligible a proposition, and imply no more contradiction than the affirmation, that it will rise. We shall in vain, therefore, attempt to demonstrate its falsehood. Where it demonstratively false, it would imply a contradiction, and could never be distinctly conceived by the mind.

These two categories are the objects of human reason, but the kinds of knowledge they produce differs. Matters of fact have features contrary to relations of ideas; (i) they are not intuitively certain and not demonstrable. (ii) They can never imply contradiction and assert existence of non-abstract entities, and (iii) the knowledge about them is a posteriori, they are beliefs that claim to report the nature of existing things; they are always contingent. It is this type of proposition that characterizes most of man’s claim to knowledge. It results from people’s interaction with the external world. The question that arises from this is, how possible is it for one to know what is outside one’s own experience? Knowledge of such depends upon the principle of induction and the uniformity of nature. Induction is employed by the physical sciences to ascend from the concrete, isolated, individual occurrences of nature to the generalized, universal, necessary laws which govern these phenomena. While the principle of uniformity of nature means that there are regularities and order in nature which make us suppose that the future will be the same as the past.


What is the evidence which assures us of any real existence and matters of fact beyond the present testimony of our senses, or the records of our memory? How is matter of fact intuitively certain or demonstrable? What is the evidence from which the truth of unobservable matters of fact, for example, the sun will rise tomorrow is justified? All our possible reasoning with respect to matter of fact and existence are built upon the two concepts of cause and effect, which enable us to go beyond the evidence of our memory and senses. The hearing of an articulate voice and rational discourse in the dark assures us of the presence of some persons. This is because the sound of a rational voice is the effect of someone talking. The knowledge of matters of fact presuppose a belief in the causal nexus of nature. Knowledge of causal relations is based on experience: the knowledge of this relation is not attained by reasoning a priori; but arises entirely from experience.

The belief that the sun will rise tomorrow is built on the foundation of causal assumption, along with the conviction that the causal relationships of the past always remains constant. The most prevalent and important applications of hypothetical inductive reasoning has to do with figuring out the inner mechanism of a thing. That is, determining the causes and effects of things. In figuring out the working principle of what is causing the little clicking noise at 40 miles per hour, or what the environmental, psychological, and social consequences of the development of virtual reality technology would be; we never directly observe causal relations, we never infer them with deductive conviction, rather we must reason inductively about them. However, reasoning about causes by means of simple inductive generalization turns out not to be very reliable, due to the fact that inductive generalization by itself provides no basis for distinguishing between a causal relationship and a mere coincidence. Based on this fact, induction as a basis of causality is faulty. Our sense does not perceive causality but only perceives succession, that is, causality is just an invention of the mind. Knowledge could only consist of intuitively obvious matters or demonstrable relations of ideas but not of anything beyond experience; the mind can discover no necessary connections within experience nor any root causes of experience. Beliefs about the world are based not upon reason or evidence or even upon appeal to the uniformity of nature but only on habit and custom.



What is it that makes it so certain that the future will behave like the past? If our answer is that, because it has always done so in the past, we are simply begging the question, because the real question is, must it be so in the future just because it has always been so in the past? We can’t appeal to the laws of nature, because then, the question is, what guarantees that the laws of nature will hold tomorrow? Thus, for any argument to be valid and logical, it has to be characterized by the fact that, if the premise of the argument is true, then the conclusion must necessarily be true. In this consideration, however, inductive argument does not have this feature, only deductive arguments possess this character. The principle of induction would certainly be justified if inductive arguments are valid and logical, but they are not; as such induction cannot be justified purely on logical grounds.

The concept of causality which states that nothing exists without a cause cannot be demonstrated by rational arguments, but by experience alone. Above all, it is from observation and experience that habit is produced. When we examine habit to see how they are actually produced, we discover that they arise after we have experienced two things that follow each other. For instance, when I observe the constant conjunction between two events in my experience, I grow accustomed to associating them with each other in as much as it continues to resemble the past. More so, although many past cases of sunrise that I have experienced do not guarantee the future of nature to remain the same, my experience of them indeed gets me used to the idea and produces in me an expectation that the sun will rise again tomorrow. However, I cannot prove that it will, but I feel that it must. Thus, habit is the principle that determines us to form such conclusions; reason is incapable of any such variation. Habit then, is the guide of human life. It is that principle alone which renders our experience useful to us, and makes us expect for the future, a similar train of events with those which have appeared in the past. Without the influence of habit, we are entirely ignorant of every matter of fact beyond what is immediately present to the memory and sense.

For example: our belief that the sun will rise tomorrow rests on a foundation that needs justification itself. Clearly, this is a matter of fact; it rests on our conviction that each sunrise is an effect caused by the rotation of the earth. But our belief in that causal relation or causal reasoning is based on past observations, and our confidence that it will continue tomorrow cannot be justified by reference to the past. If we be, therefore, engaged by arguments to put trust in past experience, and make it the standard of our future judgment, these arguments must be probable only. So, we have no rational basis for believing that the sun will rise tomorrow.

Genuine knowledge has to be eternal, not such that is conjecture today and becomes refuted tomorrow. Experience has shown that there is no such knowledge that is eternal, and since the basis of account of reality, namely: principle of uniformity of nature, induction, and causality, cannot be objectively verified; therefore there cannot be such knowledge to be termed objective. In reality, all arguments from experience are founded on the similarity which we discover among natural objects, and by which we are induced to expect effects similar to those which we have found to follow from such objects. Hence, since knowledge cannot be drawn based on similarity, there can be no objectivity in knowledge of reality.

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