Do You Know That the Sun Will Rise Tomorrow?

Do you know that the sun will rise tomorrow?

        The question of whether or not the sun will rise tomorrow is one that many people would not consider very thoroughly, due to it seeming to be such an obvious regularity. Whether we believe this as a blind outcome of past experience, or can justify it with reasonable belief (Russell, 2011) is a matter of debate. The belief that the sun will rise tomorrow and will continue to in the future is held because it has risen every day previously. If one was challenged on holding this belief, they would probably appeal to the laws of motion, which have always been uniform in nature, so it is feasible to suggest that they will remain so until tomorrow. (Russell, 2011) However, David Hume believed that no innate concepts exist, so although we all reason inductively, we cannot have justification for these beliefs as we can only acquire knowledge through experience. Therefore, Hume would suggest that one cannot know that the sun will rise tomorrow, because an inductively strong argument can be false no matter how many observations we make. In this essay, I will outline Hume’s main argument against induction, and present the possible solutions to this problem. I will conclude that, although we cannot know with certainty that the sun will rise tomorrow, as it is an unobserved event, based on past experience we are justified in saying that it is probable.

        Hume approach is naturalistic, and he proposes that our minds are like inductive engines which take experience and generate beliefs. (Ladyman, 2007) He suggests that if something contains neither ‘abstract reasoning concerning quantity or numbers, nor experimental reasoning concerning matter of fact and existence, then it is merely sophistry and illusion.’ (Ladyman, 2007) So, in order to grasp our knowledge of matters of fact we need to assess the relation of cause and effects, which can only be obtained through experience, because the ideas involved are logically unrelated. The nature of this experience must be understood to see if it can justify our inductive practices. (Ladyman, 2007) In ‘Hume’s Treatise of Human Nature’ he states that ‘it is false that instances of which we have had no experience must resemble those of which we have had experience’ (Hume, 1888) because ‘the course of nature may change, and […] the past may be no rule for the future.’ (Hume, 1995) Hume, therefore, believes that we have no more reason to believe that the sun will rise tomorrow than to believe that it will not, because there is no contradiction in assuming that a causal relation does not hold. Despite this sceptical view, Hume states that ‘nature, by an absolute and uncontrollable necessity, has determined me to judge as well as to breathe and feel’, suggesting that judgement is a necessity, and therefore impossible to suspend.

        The Humean analysis of causation is the belief in contiguity, which is ‘the relation of being connected in space and time.’ (Ladyman, 2007) This suggests that because we cannot see the necessary connection between cause and effect we have no reason to believe there is one at all, which contrasts with the necessarian view that there is a connection. Hume disagrees with the necessarian view by suggesting that we only connect similar events with similar effects based on habit not reason. He proposes that the necessitarian and Humean explanations present the same view about causal relations, but the latter is less complex, and according to a principle called ‘Occam’s razor’, the simpler of the two is preferred. (Ladyman, 2007) By this analysis, Hume is suggesting that it is always possible that a causal relation will be different in the future. This is displayed in Bertrand Russell’s ‘The Problems of Philosophy’ (2011), when he speaks of a man who has fed a chicken everyday of its life, then eventually wrings its neck. This shows that the uniformity of nature which we appeal to in order to believe that the sun will rise tomorrow does not always necessarily hold up. The moral here is that we are possibly no better off than the chicken, so are not justified in expecting such uniformity.

        To seek an answer to whether or not the sun will rise tomorrow, it seems reasonable to appeal to the laws of motion. The earth has always rotated around the sun causing the sun to rise, so it is likely that this will remain in operation until tomorrow. However, Russell notes that science and everyday assumptions both rely on induction, as ‘the only evidence we have for their truths is what we have previously observed.’^[1] Therefore, if Hume is correct, our scientific knowledge is without rational foundation. Despite this, although we may not know the truth of scientific theories or that the sun will rise tomorrow for certain, inductive reasoning still gives us good reason to believe both are likely to be true.^[2]