Hume's dilema

omar · February 8, 2008, 6:24pm

Hume says:
Let us become thoroughly sensible of the weakness, blindness and narrow limits of human reason…

Yet how can he do that? Where does he form this conclusion? If Hume is right then he is faced with the liar’s dilema, for if he is right then neither he nor myself could become THOROUGHLY sensible, while being at the same time BLIND and narrow?

Oni_Omega · February 8, 2008, 6:45pm

Sensationalist contrarians.

Baneful.

Juggernaut · February 10, 2008, 3:17am

If you use reason and try to act out of reason, and are reasonable, you never get a sense of all that is beyond the limit of reason. How often do you see people try to apply reason to human behavior when clearly the bulk of it is motivated by emotions. So, I think Hume was pushing an emotinal consciousness where each person bravely considers the tools of reason against the task of ignorence, and then takes the only other available tool we have on hand, which is sensitivity to options, to insight, to imagination, to the outrageaous, and the impossible; because there we may find new applications for reason. We experience life with our senses, and we order reality with our thoughts, but the stage between these two, where we wrestle with unknowns, and fears, undefined problems, and problematic definitions, in our subconscious minds is were the great work of mankind is always done on a budget. Give it time. Let it off its leash.

more_or_less · February 10, 2008, 5:00am

Having knowledge of your flaws means you can proceed in spite of them, but with respect for them and of them. I seem to recall that it really comes down to being reasonable, and using common sense.

Is it not a greater dilemma to be paralyzed by your faults or limitations into complete inaction?

Juggernaut · February 10, 2008, 2:45pm

Hume is not saying personal reason, but human reason. The flaw is the expectation that reality behaves in a reasonable fashion according to what we know as reasonable, and it never does. Reasonable was not the same after Copernicus, after Darwin, or after Freud. So logic does not lead us to the next great discovery, but can only point out the failures of the current theory.

more_or_less · February 10, 2008, 5:47pm

That is a gross misstatement, imho. The point is we will never have KNOWLEDGE of the future, knowledge implying certainty. There is no telling what “reality does” or will do, that’s the point. Not that it “never does” what we expect. I’ll be damned disappointed the day the sun does not “rise.”

Reasonable men make a theory, generate a hypothesis, test it, and make a claim predicated on probability from the evidence they have found. Then Imp comes along, calls it psuedo-science, and then pointlessly attacks your assumptions.

That’s how it works.

Hume claims we need to trust our senses, and our faculties of reason, while remaining skeptical of the certainty of our “knowledge claims.”

Impenitent · February 11, 2008, 3:15am

more or less:

That is a gross misstatement, imho. The point is we will never have KNOWLEDGE of the future, knowledge implying certainty. There is no telling what “reality does” or will do, that’s the point. Not that it “never does” what we expect. I’ll be damned disappointed the day the sun does not “rise.”

Reasonable men make a theory, generate a hypothesis, test it, and make a claim predicated on probability from the evidence they have found. Then Imp comes along, calls it psuedo-science, and then pointlessly attacks your assumptions.

I do not call it pseudo science. I call it illogical and irrational. pointlessly attacking assumptions? as if assumptions were truth…

That’s how it works.

Hume claims we need to trust our senses, and our faculties of reason, while remaining skeptical of the certainty of our “knowledge claims.”

-Imp

more_or_less · February 11, 2008, 7:49pm

Impenitent:

more or less:

That is a gross misstatement, imho. The point is we will never have KNOWLEDGE of the future, knowledge implying certainty. There is no telling what “reality does” or will do, that’s the point. Not that it “never does” what we expect. I’ll be damned disappointed the day the sun does not “rise.”

Reasonable men make a theory, generate a hypothesis, test it, and make a claim predicated on probability from the evidence they have found. Then Imp comes along, calls it psuedo-science, and then pointlessly attacks your assumptions.

I do not call it pseudo science. I call it illogical and irrational. pointlessly attacking assumptions? as if assumptions were truth…

That’s how it works.

Hume claims we need to trust our senses, and our faculties of reason, while remaining skeptical of the certainty of our “knowledge claims.”

-Imp

Will you see the sun again, Imp?

Also, assumption are not truth claims. Assumptions are just that, assumptions.

Impenitent · February 12, 2008, 4:03am

assumptions masquerading as godly truths and “laws” of science?

-Imp

more_or_less · February 12, 2008, 11:01pm

Are you saying that you being deceived so as not to trust your sensory perceptions? How is the consistency of the past not a probable indicator of the future? Again, science does not claim to have knowledge of the future, only a probability of events.

but if you think fire will not be hot tomorrow, I encourage you to stick your head in your oven and let me know…

BrazenBull · February 12, 2008, 11:37pm

Recognizing the shortcomings of the human faculty of reason doesn’t require the same kind of objectivist certainty required to take the stance that no knowledge is beyond the scope of our ability.

Hume can be seen as taking a bit of a leap of faith in assuming the objective reality of human reason’s shortcomings, and with this in mind I think I see the point of the original post.

If I may step outside of Hume’s intended point and take a stab at why his claim is more desirable than the alternative even if it is a bit hypocritical:
In the context of scientific inquiry, an approach gathering knowledge that is characterized by a degree of humility lends itself far more to thoroughness and double-checking than an overconfident approach.
I actually agree with Hume and think that the expectation that a lump of cells that evolved to fill a niche in Earth’s environment can digest and synthesize data in a truly reliably objective fashion is absurd. But I think that these kinds of points are really moot, because when we bump up against that which we’re not equipped to perceive, it’s likely that we won’t even realize it. Worrying about it doesn’t get us anywhere in life as we experience it, though, so we have to treat the fruit of thoroughgoing humble endeavors within our narrow scope of experience as if it is objective and universally applicable. As far as we’re concerned, anyway.
That’s probably a dangerous slippery slope, but it’s the way quests for knowledge have always proceeded (as far as I’m aware). We improve upon the old paradigm, tout the new one as Truth, and hold fast until further refinements come along. I just find it hard to believe we’re working toward objective perfection.

I’m pretty sure I’m not making any sense. Just kind of riffing at this point.

Juggernaut · February 13, 2008, 12:29am

BrazenBull:

Recognizing the shortcomings of the human faculty of reason doesn’t require the same kind of objectivist certainty required to take the stance that no knowledge is beyond the scope of our ability.

Hume can be seen as taking a bit of a leap of faith in assuming the objective reality of human reason’s shortcomings, and with this in mind I think I see the point of the original post.

If I may step outside of Hume’s intended point and take a stab at why his claim is more desirable than the alternative even if it is a bit hypocritical:
In the context of scientific inquiry, an approach gathering knowledge that is characterized by a degree of humility lends itself far more to thoroughness and double-checking than an overconfident approach.
I actually agree with Hume and think that the expectation that a lump of cells that evolved to fill a niche in Earth’s environment can digest and synthesize data in a truly reliably objective fashion is absurd. But I think that these kinds of points are really moot, because when we bump up against that which we’re not equipped to perceive, it’s likely that we won’t even realize it. Worrying about it doesn’t get us anywhere in life as we experience it, though, so we have to treat the fruit of thoroughgoing humble endeavors within our narrow scope of experience as if it is objective and universally applicable. As far as we’re concerned, anyway.
That’s probably a dangerous slippery slope, but it’s the way quests for knowledge have always proceeded (as far as I’m aware). We improve upon the old paradigm, tout the new one as Truth, and hold fast until further refinements come along. I just find it hard to believe we’re working toward objective perfection.

I’m pretty sure I’m not making any sense. Just kind of riffing at this point.

I think you are making sense. Especially about bumping into what we are not equipped to percieve which we do with moral reality all the time. As important, what we think of as logical is the way nature behaves; but much of what nature does we do not see the logic in because of our own expectations of what is logical to expect. So, logic gives us the ability to check some things, and to organize our knowledge; but I doubt its use in much of a possitive and creative fashion since it leads us too much into preconceptions, and blinds us. Now, I might be able to support some of what I say from evidence from the past. It is naturally not possible to suggest examples in the future, but only to say that when new truths are discovered they come with their own new logic that immediatly makes sense, then, and not before.

Impenitent · February 13, 2008, 5:27am

there is no logical reason to believe that the future will be like the past…

-Imp

Dan1 · February 13, 2008, 6:19am

Becoming sensible about the weaknesses and limits of human facilities. How would that be part of, or related to a liar’s diema? Wouldn’t it instead be the opposite?

It’s disturbingly amazing that so many have posted already in the way that they have, to the simple and obvious basics quoted from Hume about human reason.

Juggernaut · February 13, 2008, 1:36pm

I have to disagree with this. Repetition is the rule, the same cause having the same effect indefinetly. What I don’t think one can argue for is an indefinite sequence based upon what seems logically true today. It is easy to misunderstand all the many ways effects can become causes, or the way slight changes can ripple through systems, or the playing out of unforseen consequences. So, while we can say quite reliably what will happen tomorrow that does not give us the ability to predict long term. Even the geological history of the earth shows that change is the norm, and some times, catastrophic change at that. Even where a certain being can be predicated, if we are not here individually or as humanity to witness it, it will have no meaning; and for us, meaning is the essential quality to being. No us, no it.

Faust · February 13, 2008, 3:32pm

As Imp alludes to here, and as I have alluded to in the past, Hume is, at bottom, attacking not reason itself, but rationalism. Hume practised an approach that is still used today - professional politesse. Hume clearly wanted to be accepted by the academic community. So he pussyfooted a little. All the while writing an iconoclastic theory.

He is claiming limits to human reason - and not that human reason is entirely impotent. As an empiricist, which he more or less was, he claims that reason alone means nothing - this in contradistinction to the rationalists. Reason must be applied to data gained through the senses - at leat indirectly - to be of any use. No one trusted his senses more than Hume - he had nothing to say without sensory data. These are the narrow limits.

Hume removed time from empiricism. This turned out to be a rather odd feature of his thinking, but it got the job done. I don’t think he is strictly correct in doing so, but he is close enough that it does not affect his major idea - that we cannot know God - particularly in a Cartesian way. It was Descartes, most immediately, but therefore also Plato and Aristotle, that he sought to answer. Within this context, the provided quote is not problematic.

more_or_less · February 13, 2008, 11:53pm

“believe”? meh.

so, how is it that “logic” is a valid basis of criticism for empirical claims of probability? It seems logical criticism would be for “known values,” and theorems, a’la math.

Again the claim Hume is critical of is claiming to have “knowledge” of the future. I really doubt you could find source on Hume where he would state its irrational to have any expectations of any outcomes, only that it is a logical error to claim to have knowledge of the outcomes based on the past experiences. It is not irrational to make the claims in and of themselves.

ie, it is both rational and reasonalbe to expect, within probability, that the sun will rise tomorrow. It would only be irrational to claim I know that it will rise tomorrow.

Impenitent · February 14, 2008, 12:35am

more or less:

Impenitent:

there is no logical reason to believe that the future will be like the past…

-Imp

“believe”? meh.

so, how is it that “logic” is a valid basis of criticism for empirical claims of probability? It seems logical criticism would be for “known values,” and theorems, a’la math.

Again the claim Hume is critical of is claiming to have “knowledge” of the future. I really doubt you could find source on Hume where he would state its irrational to have any expectations of any outcomes, only that it is a logical error to claim to have knowledge of the outcomes based on the past experiences.

class.uidaho.edu/mickelsen/t … PART%20III.

It is not irrational to make the claims in and of themselves.

ie, it is both rational and reasonalbe to expect, within probability, that the sun will rise tomorrow. It would only be irrational to claim I know that it will rise tomorrow.

if by rational you mean follows the rules of logic, it is not rational
if by reasonable you mean follows reason i.e. rules of logic, it is not reasonable

“within probability” - you mean a blind guess about unseen events that may or may not occur…

we do not agree.

-Imp

more_or_less · February 14, 2008, 4:38am

I didn’t realize a LINK was the same as SOURCE BASED TEXT…

You’ve misapplied Hume to “all scientific methods” for his criticism only over pure reasoning about cause to effect

Let men be once fully perswaded of these two principles, That there, is nothing in any object, consider’d in itself, which can afford us a reason for drawing a conclusion beyond it; and, That even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience; I say, let men be once fully convinc’d of these two principles, and this will throw them so loose from all common systems, that they will make no difficulty of receiving any, which may appear the most extraordinary. These principles we have found to be sufficiently convincing, even with regard to our most certain reasonings from causation: But I shall venture to affirm, that with regard to these conjectural or probable reasonings they still acquire a new degree of evidence.

in reasoning alone

Most of what Hume discusses is the relation/connection of cause to effect. necessary/contignet/analogy etc

and then…

SECT. XV.

Rules by which to judge of Causes and Effects.

According to the precedent doctrine, there are no objects which by the mere survey, without consulting experience, we can determine to be the causes of any other; and no objects, which we can certainly determine in the same manner not to be the causes. Any thing may produce any thing. Creation, annihilation, motion, reason, volition; all these may arise from one another, or from any other object we can imagine. Nor will this appear strange, if we compare two principles explain’d above, that the constant conjunction of objects determines their causation, and(31) that, property speaking, no objects are contrary to each other but existence and non-existence. Where objects are not contrary, nothing hinders them from having that constant conjunction, on which the relation of cause and effect totally depends.

Since therefore 'tis possible for all objects to become causes or effects to each other, it may be proper to fix some general rules, by which we may know when they really are so.

(1) The cause and effect must be contiguous in space and time.

(2) The cause must be prior to the effect.

(3) There must be a constant union betwixt the cause and effect. 'Tis chiefly this quality, that constitutes the relation.

(4) The same cause always produces the same effect, and the same effect never arises but from the same cause. This principle we derive from experience, and is the source of most of our philosophical reasonings. For when by any clear experiment we have discovered the causes or effects of any phaenomenon, we immediately extend our observation to every phenomenon of the same kind, without waiting for that constant repetition, from which the first idea of this relation is deriv’d.

(5) There is another principle, which hangs upon this, viz. that where several different objects produce the same effect, it must be by means of some quality, which we discover to be common amongst them. For as like effects imply like causes, we must always ascribe the causation to the circumstance, wherein we discover the resemblance.

(6) The following principle is founded on the same reason. The difference in the effects of two resembling objects must proceed from that particular, in which they differ. For as like causes always produce like effects, when in any instance we find our expectation to be disappointed, we must conclude that this irregularity proceeds from some difference in the causes.

(7) When any object encreases or diminishes with the encrease or diminution of its cause, 'tis to be regarded as a compounded effect, deriv’d from the union of the several different effects, which arise from the several different parts of the cause. The absence or presence of one part of the cause is here suppos’d to be always attended with the absence or presence of a proportionable part of the effect. This constant conjunction sufficiently proves, that the one part is the cause of the other. We must, however, beware not to draw such a conclusion from a few experiments. A certain degree of heat gives pleasure; if you diminish that heat, the pleasure diminishes; but it does not follow, that if you augment it beyond a certain degree, the pleasure will likewise augment; for we find that it degenerates into pain.

(8) The eighth and last rule I shall take notice of is, that an object, which exists for any time in its full perfection without any effect, is not the sole cause of that effect, but requires to be assisted by some other principle, which may forward its influence and operation. For as like effects necessarily follow from like causes, and in a contiguous time and place, their separation for a moment shews, that these causes are not compleat ones.

Here is all the LOGIC I think proper to employ in my reasoning; and perhaps even this was not very necessary, but might have been supplyd by the natural principles of our understanding. Our scholastic head-pieces and logicians shew no such superiority above the mere vulgar in their reason and ability, as to give us any inclination to imitate them in delivering a long system of rules and precepts to direct our judgment, in philosophy. All the rules of this nature are very easy in their invention, but extremely difficult in their application; and even experimental philosophy, which seems the most natural and simple of any, requires the utmost stretch of human judgment. There is no phaenomenon in nature, but what is compounded and modifyd by so many different circumstances, that in order to arrive at the decisive point, we must carefully separate whatever is superfluous, and enquire by new experiments, if every particular circumstance of the first experiment was essential to it. These new experiments are liable to a discussion of the same kind; so that the utmost constancy is requird to make us persevere in our enquiry, and the utmost sagacity to choose the right way among so many that present themselves. If this be the case even in natural philosophy, how much more in moral, where there is a much greater complication of circumstances, and where those views and sentiments, which are essential to any action of the mind, are so implicit and obscure, that they often escape our strictest attention, and are not only unaccountable in their causes, but even unknown in their existence? I am much afraid lest the small success I meet with in my enquiries will make this observation bear the air of an apology rather than of boasting.

If any thing can give me security in this particular, 'twill be the enlarging of the sphere of my experiments as much as possible; for which reason it may be proper in this place to examine the reasoning faculty of brutes, as well as that of human creatures.

pts 1 thru 4, plus the section I bolded are what underscore the notion of repeating the results, isolating the cause, etc. Hume is laying THE FOUNDATION for the scientific method, not being critical of it as you suppose. He is being critical of “thought experiments” devoid of connection to the ongoing, rigorous application of method.

concludes

the reasoning must hold to experience [aka evidence]

SECT. I.

Of Scepticism with regard to Reason.

In every judgment, which we can form concerning probability, as well as concerning knowledge, we ought always to correct the first judgment, deriv’d from the nature of the object, by another judgment, deriv’d from the nature of the understanding. 'Tis certain a man of solid sense and long experience ought to have, and usually has, a greater assurance in his opinions, than one that is foolish and ignorant, and that our sentiments have different degrees of authority, even with ourselves, in proportion to the degrees of our reason and experience. In the man of the best sense and longest experience, this authority is never entire; since even such-a-one must be conscious of many errors in the past, and must still dread the like for the future. Here then arises a new species of probability to correct and regulate the first, and fix its just standard and proportion. As demonstration is subject to the controul of probability, so is probability liable to a new correction by a reflex act of the mind, wherein the nature of our understanding, and our reasoning from the first probability become our objects.

and boo-yah

coherence and the senses

Having found that the opinion of the continu’d existence of body depends on the COHERENCE, and CONSTANCY of certain impressions, I now proceed to examine after what manner these qualities give rise to so extraordinary an opinion. To begin with the coherence; we may observe, that tho’ those internal impressions, which we regard as fleeting and perishing, have also a certain coherence or regularity in their appearances, yet ‘tis of somewhat a different nature, from that which we discover in bodies.’

[…]

There is scarce a moment of my life, wherein there is not a similar instance presented to me, and I have not occasion to suppose the continu’d existence of objects, in order to connect their past and present appearances, and give them such an union with each other, as I have found by experience to be suitable to their particular natures and circumstances. Here then I am naturally led to regard the world, as something real and durable, and as preserving its existence, even when it is no longer present to my perception.

he goes on to qualify that, greatly.

concludes

Nor is it only proper we shou’d in general indulge our inclination in the most elaborate philosophical researches, notwithstanding our sceptical principles, but also that we shou’d yield to that propensity, which inclines us to be positive and certain in particular points, according to the light, in which we survey them in any particular instant. 'Tis easier to forbear all examination and enquiry, than to check ourselves in so natural a propensity, and guard against that assurance, which always arises from an exact and full survey of an object. On such an occasion we are apt not only to forget our scepticism, but even our modesty too; and make use of such terms as these, 'tis evident, 'tis certain, 'tis undeniable; which a due deference to the public ought, perhaps, to prevent. I may have fallen into this fault after the example of others; but I here enter a caveat against any Objections, which may be offer’d on that head; and declare that such expressions were extorted from me by the present view of the object, and imply no dogmatical spirit, nor conceited idea of my own judgment, which are sentiments that I am sensible can become no body, and a sceptic still less than any other.

thus “knowledge claims” should be “it appears” the “data suggests” there is a “high probability” or a “degree of certainty [oxymoron, imho]”. Those would be, according to Hume, both reasonable and rational claims, based on the conditionals outlined above.

Impenitent · February 14, 2008, 12:02pm

more or less:

I didn’t realize a LINK was the same as SOURCE BASED TEXT…

Hume:

There remain, therefore, algebra and arithmetic as the only sciences, in which we can carry on a chain of reasoning to any degree of intricacy, and yet preserve a perfect exactness and certainty.

of course for hume, algebra and arithmetic are a priori and tell one nothing about the world outside of the definitions of the mathematical systems.

You’ve misapplied Hume to “all scientific methods” for his criticism only over pure reasoning about cause to effect

Let men be once fully perswaded of these two principles, That there, is nothing in any object, consider’d in itself, which can afford us a reason for drawing a conclusion beyond it; and, That even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience; I say, let men be once fully convinc’d of these two principles, and this will throw them so loose from all common systems, that they will make no difficulty of receiving any, which may appear the most extraordinary. These principles we have found to be sufficiently convincing, even with regard to our most certain reasonings from causation: But I shall venture to affirm, that with regard to these conjectural or probable reasonings they still acquire a new degree of evidence.

in reasoning alone

That there, is nothing in any object, consider’d in itself, which can afford us a reason for drawing a conclusion beyond it; and, That even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience;

no conclusions beyond that which is immediately sensed. - I misapply nothing, the “truth” of science is laid bare.

The first may be explain’d after this manner. When the mind forms a reasoning concerning any matter of fact, which is only probable, it casts its eye backward upon past experience, and transferring it to the future, is presented with so many contrary views of its object, of which those that are of the same kind uniting together, and running into one act of the mind, serve to fortify and inliven it. But suppose that this multitude of views or glimpses of an object proceeds not from experience, but from. a voluntary act of the imagination; this effect does not follow

Most of what Hume discusses is the relation/connection of cause to effect. necessary/contignet/analogy etc

and then…

SECT. XV.

Rules by which to judge of Causes and Effects.

According to the precedent doctrine, there are no objects which by the mere survey, without consulting experience, we can determine to be the causes of any other; and no objects, which we can certainly determine in the same manner not to be the causes. Any thing may produce any thing. Creation, annihilation, motion, reason, volition; all these may arise from one another, or from any other object we can imagine. Nor will this appear strange, if we compare two principles explain’d above, that the constant conjunction of objects determines their causation, and(31) that, property speaking, no objects are contrary to each other but existence and non-existence. Where objects are not contrary, nothing hinders them from having that constant conjunction, on which the relation of cause and effect totally depends.

Since therefore 'tis possible for all objects to become causes or effects to each other, it may be proper to fix some general rules, by which we may know when they really are so.

(1) The cause and effect must be contiguous in space and time.

(2) The cause must be prior to the effect.

(3) There must be a constant union betwixt the cause and effect. 'Tis chiefly this quality, that constitutes the relation.

(4) The same cause always produces the same effect, and the same effect never arises but from the same cause. This principle we derive from experience, and is the source of most of our philosophical reasonings. For when by any clear experiment we have discovered the causes or effects of any phaenomenon, we immediately extend our observation to every phenomenon of the same kind, without waiting for that constant repetition, from which the first idea of this relation is deriv’d.

(5) There is another principle, which hangs upon this, viz. that where several different objects produce the same effect, it must be by means of some quality, which we discover to be common amongst them. For as like effects imply like causes, we must always ascribe the causation to the circumstance, wherein we discover the resemblance.

(6) The following principle is founded on the same reason. The difference in the effects of two resembling objects must proceed from that particular, in which they differ. For as like causes always produce like effects, when in any instance we find our expectation to be disappointed, we must conclude that this irregularity proceeds from some difference in the causes.

(7) When any object encreases or diminishes with the encrease or diminution of its cause, 'tis to be regarded as a compounded effect, deriv’d from the union of the several different effects, which arise from the several different parts of the cause. The absence or presence of one part of the cause is here suppos’d to be always attended with the absence or presence of a proportionable part of the effect. This constant conjunction sufficiently proves, that the one part is the cause of the other. We must, however, beware not to draw such a conclusion from a few experiments. A certain degree of heat gives pleasure; if you diminish that heat, the pleasure diminishes; but it does not follow, that if you augment it beyond a certain degree, the pleasure will likewise augment; for we find that it degenerates into pain.

(8) The eighth and last rule I shall take notice of is, that an object, which exists for any time in its full perfection without any effect, is not the sole cause of that effect, but requires to be assisted by some other principle, which may forward its influence and operation. For as like effects necessarily follow from like causes, and in a contiguous time and place, their separation for a moment shews, that these causes are not compleat ones.

Here is all the LOGIC I think proper to employ in my reasoning; and perhaps even this was not very necessary, but might have been supplyd by the natural principles of our understanding. Our scholastic head-pieces and logicians shew no such superiority above the mere vulgar in their reason and ability, as to give us any inclination to imitate them in delivering a long system of rules and precepts to direct our judgment, in philosophy. All the rules of this nature are very easy in their invention, but extremely difficult in their application; and even experimental philosophy, which seems the most natural and simple of any, requires the utmost stretch of human judgment. There is no phaenomenon in nature, but what is compounded and modifyd by so many different circumstances, that in order to arrive at the decisive point, we must carefully separate whatever is superfluous, and enquire by new experiments, if every particular circumstance of the first experiment was essential to it. These new experiments are liable to a discussion of the same kind; so that the utmost constancy is requird to make us persevere in our enquiry, and the utmost sagacity to choose the right way among so many that present themselves. If this be the case even in natural philosophy, how much more in moral, where there is a much greater complication of circumstances, and where those views and sentiments, which are essential to any action of the mind, are so implicit and obscure, that they often escape our strictest attention, and are not only unaccountable in their causes, but even unknown in their existence? I am much afraid lest the small success I meet with in my enquiries will make this observation bear the air of an apology rather than of boasting.

If any thing can give me security in this particular, 'twill be the enlarging of the sphere of my experiments as much as possible; for which reason it may be proper in this place to examine the reasoning faculty of brutes, as well as that of human creatures.

pts 1 thru 4, plus the section I bolded are what underscore the notion of repeating the results, isolating the cause, etc. Hume is laying THE FOUNDATION for the scientific method, not being critical of it as you suppose.

he is doing no such thing. "That there, is nothing in any object, consider’d in itself, which can afford us a reason for drawing a conclusion beyond it; and, That even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience;"

He is being critical of “thought experiments” devoid of connection to the ongoing, rigorous application of method.

you have to remember that he has denied the logical validity of inductive arguments. he has not claimed that the human does not act out of habit and the expectation of the constant conjunction of events, but he does deny that it is based in logic.

concludes

Since therefore all knowledge resolves itself into probability, and becomes at last of the same nature with that evidence, which we employ in common life, we must now examine this latter species of reasoning, and see on what foundation it stands.

the reasoning must hold to experience [aka evidence]

SECT. I.

Of Scepticism with regard to Reason.

In every judgment, which we can form concerning probability, as well as concerning knowledge, we ought always to correct the first judgment, deriv’d from the nature of the object, by another judgment, deriv’d from the nature of the understanding. 'Tis certain a man of solid sense and long experience ought to have, and usually has, a greater assurance in his opinions, than one that is foolish and ignorant, and that our sentiments have different degrees of authority, even with ourselves, in proportion to the degrees of our reason and experience. In the man of the best sense and longest experience, this authority is never entire; since even such-a-one must be conscious of many errors in the past, and must still dread the like for the future. Here then arises a new species of probability to correct and regulate the first, and fix its just standard and proportion. As demonstration is subject to the controul of probability, so is probability liable to a new correction by a reflex act of the mind, wherein the nature of our understanding, and our reasoning from the first probability become our objects.

and boo-yah

I had almost said, that this was certain; but I reflect that it must reduce itself, as well as every other reasoning, and from knowledge degenerate into probability.

and this disagrees with what I claimed?

coherence and the senses

Having found that the opinion of the continu’d existence of body depends on the COHERENCE, and CONSTANCY of certain impressions, I now proceed to examine after what manner these qualities give rise to so extraordinary an opinion. To begin with the coherence; we may observe, that tho’ those internal impressions, which we regard as fleeting and perishing, have also a certain coherence or regularity in their appearances, yet ‘tis of somewhat a different nature, from that which we discover in bodies.’

[…]

There is scarce a moment of my life, wherein there is not a similar instance presented to me, and I have not occasion to suppose the continu’d existence of objects, in order to connect their past and present appearances, and give them such an union with each other, as I have found by experience to be suitable to their particular natures and circumstances. Here then I am naturally led to regard the world, as something real and durable, and as preserving its existence, even when it is no longer present to my perception.

he goes on to qualify that, greatly.

again, he never gives a logical reason for believing in the constant conjunction. it is habit.

concludes

Nor is it only proper we shou’d in general indulge our inclination in the most elaborate philosophical researches, notwithstanding our sceptical principles, but also that we shou’d yield to that propensity, which inclines us to be positive and certain in particular points, according to the light, in which we survey them in any particular instant. 'Tis easier to forbear all examination and enquiry, than to check ourselves in so natural a propensity, and guard against that assurance, which always arises from an exact and full survey of an object. On such an occasion we are apt not only to forget our scepticism, but even our modesty too; and make use of such terms as these, 'tis evident, 'tis certain, 'tis undeniable; which a due deference to the public ought, perhaps, to prevent. I may have fallen into this fault after the example of others; but I here enter a caveat against any Objections, which may be offer’d on that head; and declare that such expressions were extorted from me by the present view of the object, and imply no dogmatical spirit, nor conceited idea of my own judgment, which are sentiments that I am sensible can become no body, and a sceptic still less than any other.

thus “knowledge claims” should be “it appears” the “data suggests” there is a “high probability” or a “degree of certainty [oxymoron, imho]”. Those would be, according to Hume, both reasonable and rational claims, based on the conditionals outlined above.

“That there, is nothing in any object, consider’d in itself, which can afford us a reason for drawing a conclusion beyond it; and, That even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience;[/b]”

nothing is “reasonable” or “rational” in drawing inferences beyond it…

-Imp