(1) we trust perceptions that work for us in navigating the world
(2) we juge by criteria RCS
(3) RE fits this criteria
(4 )enables navigation
(5) :. we are warranted to trust RE as indicative
*We assume reality by means of a Jugement
*we make such jugements based upon criteria
*Because RE fits the same criteria we are justfied in making the same assumption; ie that these experinces are idicative of a reality.
The criteria: If our experiences are:
Then we assume our eperience3s reflect reality.
VIII. The Thomas Reid Argument.
A. How do we Know the external world exists?
Philosophers have often expressed skepticism about the external world, the existence of other minds, and even one's own existence. Rene Descartes went so far as to build an elaborate system of rationalism to demonstrate the existence of the external world, beginning with his famous cogito, "I think, therefore, I am." Of course, he didn't really doubt his own existence. The point was to show the method of rationalism at work. Nevertheless, this basic point, that of epistemology (how we know what we know) has always plagued philosophy. It seems no one has ever really given an adequate account. But the important point here is not so much what philosophers have said but what most people do. The way we approach life on a daily basis the assumptions we make about the external world. Skeptics are fond of saying that it is irrational to believe things without proof. I would argue that they, an all of us, believe the most crucial and most basic things without any proof whosoever, and we live based upon those assumptions which are gleaned with no proof of their veracity at all!
B. Consider Thomas Reid's Common Sense Philosophy of Foundatinalism and Fallibalism.
The point of departure here is Reid's discussion of Hume and the problem of justification of the external world. This is discussed in lecture notes of a contemporary philosopher, G.J. Mattey, in his lecture notes.
1) Skepticism about the External World
Thomas Reid, Theory of Knowledge lecture notes.G.J. Mattey
Philosophy, UC Davis
"Consider the question whether we are justified in believing that a physical world exists. As David Hume pointed out, the skepticism generated by philosophical arguments is contrary to our natural inclination to believe that there are physical objects." "[T]he skeptic . . . must assent to the principle concerning the existence of body, tho' he cannot pretend by any arguments of philosophy to maintain its veracity. Nature has not left this to his choice, and has doubtless esteem'd it an affair of too great importance to be trusted to our uncertain reasonings and speculations. We may well ask, What causes induce us to believe in the existence of body?, but 'tis in vain to ask, Whether there be body or not? That is a point, which we must take for granted in all our reasoning." (A Treatise of Human Nature, Book I, Part IV, Section II) "Nonetheless, after considering the causes of our belief in the existence of body and finding them inadequate for the justification of that belief, Hume admitted to be drawn away form his orignal assumption that bodies exist. 'To be ingenuous, I feel myself at present . . . more inclin'd to repose no faith at all in my senses, or rather imagination, than to place in it such an implicit confidence,' because ''tis impossible upon any system to defend either our understanding or senses." His solution to these doubts was "carelessness and in-attention,' which divert the mind from skeptical arguments."
2) Reid's Defense of Commonsense Beliefs.
"Thomas Reid, who was a later contemporary of Hume's, claimed that our beliefs in the external world are justified.'I shall take it for granted that the evidence of sense, when the proper circumstances concur, is good evidence, and a just ground of belief' (Essay on the Intellectual Powers of Man, Essay IV, Chapter XX). This evidence is different from that of reasoning from premises to a conclusion, however."
"That the evidence of sense is of a different kind, needs little proof. No man seeks a reason for believing what he sees or feels; and, if he did, it would be difficult to find one. But, though he can give no reason for believing his senses, his belief remains as firm as if it were grounded on demonstration. Many eminent philosophers, thinking it unreasonable to believe when the could not shew a reason, have laboured to furnish us with reasons for believing our senses; but their reasons are very insufficient, and will not bear examination. Other philosophers have shewn very clearly the fallacy of these reasons, and have, as they imagine, discovered invincible reasons agains this belief; but they have never been able either to shake it themselves or to convince others. The statesman continues to plod, the soldier to fight, and the merchant to export and ijmport, without being in the least moved by the demonstations that have been offered of the non-existence of those things about which they are so seriously employed. And a man may as soon by reasoning, pull the moon out of her orbit, as destroy the belief of the objects of sense." (Essay on the Intellectual Powers of Man, Essay IV, Chapter XX)
"Here Reid shows himself to have foundationalist tendencies, in the sense that our beliefs about physical objects are not justified by appeal to other beliefs. On the other hand, all he has established at this point is what Hume had already observed, that beliefs about physical objects are very hard to shake off. Hume himself admitted only to lose his faith in the senses when he was deeply immersed in skeptical reflections. But why should Reid think these deeply-held beliefs are based on "good evidence" or "a just ground?" One particularly telling observation is that a philosopher's "knowledge of what really exists, or did exist, comes by another channel [than reason], which is open to those who cannot reason. He is led to it in the dark, and knows not how he came by it" (Essay on the Intellectual Powers of Man, Essay IV, Chapter XX). Philosophers "cannot account for" this knowledge and must humbly accept it s a gift of heaven."
"If there is no philosophical account of justification of beliefs about the physical world, how could Reid claim that they are justified at all? The answer is the way in which they support common sense."
"Such original and natural judgments [based on sense-experience] are, therefore, a part of that furniture which Nature hath given to the human understanding. They are the inspiration of the Almighty, no less than our notions or simple apprehensions. They serve to direct us in the common affairs of life, where our reasoning faculty would leave us in the dark. They are part of our constitution; and all the discoveries of our reason are grounded upon them. They make up what is called the common sense of mankind; and, what is manifestly contrary to any of those first principles, is what we call absurd. (An Inquiry into the Human Mind, Chapter VII, Section 4)"
"One might say that judgments from sense-experience they are justified insofar as they justify other beliefs we have, or perhaps because they are the output of a perceptual system designed by God to convey the truth. (Of course, if the latter is what gives these beliefs their justification, the claim that we are designed in this way needs to be justified as well.)"
C. In other words, We accept the existence of the external world as a matter of course merely because we perceive it.
1) Acceptance of Perceptions about the world.
But it is not merely because we percieve it that we accept it. It is because we perceive it in a particular sort of way. Because we perceive it in a regular and consistent way. This has been stated above by Reid. The common man goes on with his lot never giving a second thought to the fact that he can no more prove the veracity of the things around him than he can the existence of God or anything else in philosophy. Yet we accept it, as does the skeptic demanding his data, while we live out our lives making these assumptions all the time.