After Hume finishes showing that all our ideas are obtained from the senses, he goes on to discus the notion of cause and effect. Cause and effect lead us to infer things beyond our senses and Hume rejects this notion. Hume disagrees with cause and effect because reasoning has no place in matter of facts. Because the sun rose yesterday, we do not have any reason to believe that it will rise again tomorrow. In other words, saying that the sun may not rise tomorrow is not logically wrong. “The mind can never possibly find the effect in the supposed cause, by the most accurate scrutiny and examination” (Hume, 19). One action follows another, that is what we can only see; but the force that precipitates them is hidden from us. Hume agrees that we are accustomed to seeing certain events in constant conjunction. When an object is presented to us, it is impossible for us, by any means, discover, without experience what will result of it.
According to Hume, ideas are copied from some preceding impressions. Where is no impression, we can infer and be sure that there is no idea. But in all single operation of bodies or minds, there is nothing that neither produces any impression nor can suggest any idea of necessary connection. “And experience only teaches us, how one event constantly follows another; without instructing us in the secret connexion, which binds them together, and renders them inseparable” (Hume,43). If many uniform patterns occur, then we begin to look at the notion of cause and connection. Hume argues that we do not have a priori knowledge. “I shall venture to affirm, as a general proposition, which admits of no exception, that the knowledge of this relation (matter of facts) is not, in any instance attained by reasoning a priori; but arises entirely from experience”(Hume, 19). Between what we call cause and what we call the effect, there is no necessary connection that could be seen a priori. The effect is completely different from the cause; therefore it is not possible to discover it from the cause.
Our ideas depend on experiences, whether inwardly or outwardly. Every idea that we know such as color, sound come through experience. Other ideas such as gold mountain, mermaid are derived from single impression but are ‘compounded’ of simple ideas each of which is copied from impression. It is through the mind that we are able to recall impressions we have had in the past. According to Hume, the mind does not have its own power to know things without first haven’t experienced it. “The causes and effects are discoverable, not by reason, but experience ...” (Hume, 17). Any idea we have is a copy of impression. Hume argues that our idea of God is derived from impressions. Not the experiencing of God, but it is “derived from reflection on the “the operation of our own minds and be copied from any internal impression”(Hume,42). Here Hume would be opposed to Descartes argument that because our reason conceives God, He necessarily exists. Hume suggests that our idea of God comes from our ideas of love, justices, goodness, wisdom etc... These ideas are augmented without limit to form the idea of God.
Rationalism is the theory that the use of reason, rather than experience or spiritual revelation provides the primary basis for knowledge. Descartes skepticism about the reliance of the senses as the means to a true knowledge stems from the fact that the senses sometimes deceive us. This poses to be a problem because; if the senses deceive us, it suggests that we don’t have a clue as to whether we are sleeping or dreaming. As to this end, Descartes discards all knowledge he gains through the senses and endeavors to find true knowledge by exercising his mind. Our ideas of things could be innate, self –produced or it could be caused by external forces (God). Descartes discuses about how the idea of God could not be self-produced because a finite being cannot produce the idea of an infinite being (God) If the idea of God does not come from us, it must come from God, therefore God necessarily exists. God exists not because we conceive him Descartes would agree, but because our reasons conceive God. Descartes argues that because he clearly and distinctively conceives the idea of a supreme being, he must surely exist. “But if, from the mere fact that I can bring forth from my thought the idea of something, it follows that all that I clearly and distinctly perceive to belong to that thing really does belong to it, then cannot this too be a basis for a n argument proving the existence of God”(Descartes, 43).
In meditation VI Descartes tries to prove the existence of other bodies (world of experience?). The idea of material bodies comes to Descartes even sometimes against his will, “This faculty surely cannot be in me, since it clearly presupposes no act of understanding, and these ideas are produced without my cooperation and often even against my will” (Descartes, 52). This implies that there is no way the idea of material bodies could be self-produced. If Descartes is not the cause of his sensory ideas, they could have come from either God or other bodies. But since God is not a deceiver and it must follow that the cause of sensory ideas are material bodies. Due to the fact that we can prove things about triangles without having seen any real triangle, we clearly and distinctly understand them. If we clearly and distinctly understand triangle, the same proposition also holds if we are dealing the physical world. Here Descartes argument has strength because, he refutes Hume’s argument that we have to experience things before we can understand them.
I agree with Hume’s arguments that all our ideas are based nature, rather than reason. “Our idea, therefore, of necessity and causation arises entirely from the uniformity, observable in the operations of nature; where similar objects are constantly conjoined together, and the mind is determined by custom to infer the one form the appearance of the other “(Hume, 55) We infer that the sun will rise tomorrow because we have observed that it has been rising for the past billion years. The notion of necessary connection and causation come from the fact that we have experienced “constantly conjoined” actions in the past. Free will for Hume means, the “power of acting or not acting, according to the determination of the will”(Hume, 63). I think Hume seems to be saying that an action is free if there is no other way it could have be done. Descartes on the other hand, upholds that God who has given us free will could not be the source of our sins and mistakes. Descartes argues that we only make mistakes when we do no t reason well, ie when we do not see clearly and distinctly. If Descartes argument holds here, it also implies that we do not have free will since human beings are prompt to make mistakes in our perception.
In regard to animals’ rationality, Hume believes that animals do not make use of reason in understanding. Animals cannot think and certainly, cannot reflect on ideas. Animals acquire knowledge through habit and instincts. A sheep runs away from a lion, not because of its ability to exercise reason, but through experience or natural instinct which tells it that lion is a predator.
I agree with Hume that we come to understand things by encountering and experiencing them. It is quite impossible for one to see an object and with the help of his or her mind be able to know what the object is made up of. As an empiricist, Hume does not understand how the mind on its own can be able to know things without having experienced or seen it previously. He believes that there are no connections that we know for certain between things in the world, which guarantees our conjecture about the future. Hume also says that human beings have no rational basis for believing in material things. As Hume puts it, “when we look about us towards external objects, and consider the operation of causes, we are never able, in a single instance, to discover any power or necessary connexion”(Hume, 41). He gives an example that “suppose a person, though endowed with the strongest faculties of reason and reflection, to be brought on a sudden into this world; he would, indeed, immediately observe a continual succession of objects, and one event following another; but he would not be able to discover any thing farther” (Hume, 18). One can not know for certain what is going to happen next or know some thing, just by exercising his mind on present object as Descartes proclaims.
