The Powers we have by means of our External senses No. 2 of Essays on the Intellectual Powers of Man Thomas Reid Copyright ©2010–2015 All rights reserved. Jonathan Bennett [Brackets] enclose editorial explanations. Small ·dots· enclose material that has been added, but can be read as though it were part of the original text. Occasional •bullets, and also indenting of passages that are not quotations, are meant as aids to grasping the structure of a sentence or a thought. Every four-point ellipsis. indicates the omission of a brief passage that seems to present more difficulty than it is worth. Longer omissions are reported between brackets in normal-sized type. First launched: April 2006 Last amended: May 2008 Contents Chapter 1: The organs of sense 37 Chapter 2: The impressions on the organs, nerves, and brain 39 Chapter 3: Hypotheses concerning the nerves and brain 40 Chapter 4: ·Three· false inferences from impressions on the organs etc. 46 Chapter 5: Perception 50 Chapter 6: What it is to account for a phenomenon in Nature 53 Chapter 7: What Malebranche believed about the perception of external objects 55 Powers through our external senses Thomas Reid Chapter 8: The ‘common theory’, and the views of the Aristotelians and of Descartes 60 Chapter 9: Locke’s views 69 Chapter 10: Berkeley’s views 74 Chapter 11: Berkeley’s view about the nature of ideas 79 Chapter 12: Hume’s views 85 Chapter 13: Arnauld’s views 87 Chapter 14: Thoughts about the common theory of ideas 89 Chapter 15: Leibniz’s system 98 Chapter 16: Sensation 100 Chapter 17: Objects of perception, starting with primary and secondary qualities 104 Chapter 18: Other objects of perception 111 Chapter 19: Matter and space 114 Chapter 20: The evidence of the senses, and belief in general 119 Chapter 21: Improving the senses 125 Chapter 22: The deceptiveness of the senses 127 Powers through our external senses Thomas Reid 12: Hume’s views Chapter 12: Hume’s views Two volumes of the Treatise of Human Nature were published only ideas of minds, we couldn’t infer their real existence in 1739 and the third in 1740. The doctrine contained from the existence of their ideas, any more than we can infer in this Treatise was published in a more popular form the existence of matter from the idea of it; and so, while in Hume’s Philosophical Essays, of which there have been he gives up the material world in favour of the system of several editions. [Hume died about eight years before the present ideas, he gives up half of that system in favour of the world work appeared.] What other authors from Descartes on had of minds; and maintains that we don’t need ideas to think, called ‘ideas’ Hume distinguishes into two kinds: speak, and reason intelligibly about minds and their qualities •impressions, including all our sensations, passions, and operations. and emotions; and Hume shows no such bias in favour of the world of minds. •ideas, including the faint images of impressions when He adopts the whole theory of ideas, ·not just Berkeley’s half we remember or imagine them. of it·; and that enables him to ‘show’ that the universe con- He sets out with a principle that he doesn’t offer to prove tains no matter and no minds—nothing but impressions and because he thinks it doesn’t need one, namely: ideas. What we call a ‘body’ is only a bundle of sensations; All the perceptions of the human mind come down to and what we call the ‘mind’ is only a bundle of thoughts, these two kinds—•impressions and •ideas. passions, and emotions, without any subject. ·i.e. without This proposition is the foundation on which the whole of any thing that has the thought, passion or emotion·.... Hume’s system rests, and from which it is built with great When a system of consequences is intelligently and acuteness and ingenuity; so we might wish that he had soundly inferred from a few very abstract principles, that is told us what his authority was for it. But ·he doesn’t; he· of real utility in science and may be a help towards gaining leaves us to guess whether it is offered as a self-evident real knowledge; and this is true even if the inferred system first principle or rather is to be accepted on the authority of is in itself absurd. Hume’s metaphysical writings have this philosophers. merit in high degree. Locke had taught us that all the immediate objects of It is amusing to consider that while philosophers have human knowledge are ideas in the mind. Berkeley working been labouring by means of ‘ideas’ to explain perception and from this same basis easily demonstrated that there is no the other operations of the mind, those ideas have gradually material world. He thought that for the purposes both usurped the place of perception, object, and even the mind philosophy and religion we would find no loss but great itself, supplanting the very things they were introduced benefit in getting rid of the material world. But. .he was to explain! Descartes reduced all the operations of the unwilling to give up the world of ·minds or· spirits. He clearly understanding to •perception, which is natural for someone saw that ideas are no more fit to represent minds than they who believes that those operations are only different ways are to represent bodies. Perhaps he saw that if we perceived of •perceiving ideas in our own minds. Locke runs •ideas 85 Powers through our external senses Thomas Reid 12: Hume’s views together sometimes with the •perception of an external object can be inferred from his account of the origin of our ideas, and sometimes with the •external object itself. In Berkeley’s he would probably have examined it more carefully! system the idea is the only object, and yet it is often run Hume adopts Locke’s account of the origin of our ideas, together with the perception of it. But in Hume’s system the and infers from it that we have no idea of substance, bodily idea—or the impression, which is only a more lively idea—is or mental; no idea of power; no idea of cause of x except mind, perception, and object all in one! So that by the term the idea of something that occurs before x does and is ‘perception’ in Hume’s system we must understand constantly conjoined with it; in short that we can have no •the mind itself; •all its operations, both of under- idea of anything except our sensations and the operations of standing and will; and •all the objects of these opera- mind that we are conscious of. tions. He doesn’t grant to the mind any power in forming its With ‘perception’ taken in this sense, he divides perceptions ideas and impressions; and that’s not surprising, because he into our more lively perceptions, which he calls impressions, holds that we don’t have any idea of power, and the mind is and the less lively ones, which he calls ideas. For comments, nothing but the sequence of impressions and ideas of which look back at what I said in Essay 1, chapter 1 about the we are intimately conscious. meanings of the words ‘perceive’ [item 6], ‘object’ [item 9] and ‘impression’ [item 11]. So he thinks that our impressions arise from unknown Philosophers have differed greatly with regard to the causes, and that the impressions are the causes of their origin of our ideas, the sources from which they are derived. corresponding ideas. All he means by this is that they always The Aristotelians held that all knowledge initially comes from go before the ideas; for ·according to him· that’s all that is the senses, and this ancient doctrine seems to be revived needed to constitute the relation of cause and effect. by some recent French philosophers and by Hartley and As for the order and succession of our ideas, he thinks Priestley among the British. Descartes maintained that that that is governed by •three laws of attraction or as- many of our ideas are innate. Locke energetically opposed sociation, which he takes to be basic properties of the the doctrine of innate ideas, employing the whole of Essay ideas—properties that lead ideas to attract (so to speak), or I against it. But he allows two different sources of ideas, associate themselves with, other ideas that either •resemble sensation and reflection. The main purpose of Essay II them or •have been contiguous to them in time and place is to show that absolutely all our simple ideas come from or •are related to them by the relations of cause and effect. the one or other or both of these sources. This leads Locke (Actually, the second of these seems to include the third, into some paradoxes, although in general he doesn’t care for since according to Hume causation implies nothing more paradoxes. And if he had foreseen all the consequences that than contiguity in time and place.). 86 Powers through our external senses Thomas Reid 13: Arnauld’s views Chapter 13: Arnauld’s views In this sketch of philosophers’ opinions about ideas we ·ARNAULD’S TARGET:MALEBRANCHE· must not omit Antoine Arnauld, doctor of the Sorbonne, The things that the mind perceives, says Malebranche, who in the year 1683 published his book True and False are of two kinds: they are either •in the mind itself or Ideas in opposition to the system of Malebranche that I have •external to it.