Sec 15-16: Rules on Cause, Effects; Animal Reason


  • According to the precedent doctrine, we cannot determine any object to be the cause or not the cause of any other object by the mere survey, without consulting experience.
  • Anything may produce anything.
    • All the following may arise from one another, or from any other object we can imagine.
      • Creation, annihilation, motion, reason, volition.
  • This will not appear strange if we compare two principles explained above, (Part 1. Sec. 5) that:
    • the constant conjunction of objects determines their causation
    • 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 which the relation of cause and effect totally depends on.
  • It is possible for all objects to become causes or effects to each other.
  • Thus, 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 between the cause and effect.
      • This quality chiefly constitutes the relation.
    4. The same cause always produces the same effect.
      • The same effect never arises but from the same cause.
      • We derive this principle from experience.
      • This is the source of most of our philosophical reasonings.
      • When we have discovered the causes or effects of any phenomenon by experiment, we immediately extend our observation to every phenomenon of the same kind.
        • We do not wait for that constant repetition, from which the first idea of this relation is derived.
    5. Another principle hangs on this: that where several different objects produce the same effect, it must be by means of some quality, which we discover to be common among 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 changes with change of its cause, it is to be regarded as a compounded effect derived from the union of the several effects arising from the several parts of the cause.
      • The absence or presence of one part of the cause is here supposed to be always attended with the absence or presence of a proportional part of the effect.
      • This constant conjunction sufficiently proves that the one part is the cause of the other.
      • However, we must not draw such a conclusion from a few experiments.
        • A certain degree of heat gives pleasure.
        • If you reduce that heat, the pleasure reduces.
        • 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. An object which exists for any time in its full perfection without any effect, is not the sole cause of that effect.
      • It needs to be assisted by some other principle which may forward its influence and operation because:
        • like effects follow from like causes
        • in a contiguous time and place, their separation for a moment shows that these causes are incomplete.
  • Here is all the logic to employ in my reasoning.
    • Even this was not very necessary.
    • It might have been supplied by the natural principles of our understanding.
  • Our scholastic head-pieces and logicians show no such superiority above the vulgar in their reason and ability.
    • They do not 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.
    • Experimental philosophy is the most natural and simple of any philosophy
    • Even it requires the utmost stretch of human judgment.
  • The only phenomenon in nature are those compounded and modified by so many different circumstances.
    • To arrive at the decisive point, we must:
      • carefully separate whatever is superfluous
      • inquire by new experiments, if every circumstance of the first experiment was essential to it.
        • These new experiments are liable to the same kind of discussion.
        • It will require the utmost:
          • constancy to make us persevere in our inquiry
          • sagacity to choose the right way among so many inquiries that present themselves.
  • If this is the case even in natural philosophy, how much more in moral philosophy?
    • Moral philosophy has a much greater complication of circumstances.
    • Moral views and sentiments, essential to any action of the mind, are so implicit and obscure, that they often:
      • escape our strictest attention
      • are unaccountable in their causes
      • unknown in their existence.
  • I am afraid that the small successes in my inquiries will make this observation bear the air of an apology rather than of boasting.
  • The enlarging, as much as possible, of the sphere of my experiments can give me security in this.
    • In this sphere, we can examine the reasoning faculty of brutes and human creatures.


  • Next to the ridicule of denying an evident truth, is the ridicule of taking much pains to defend it.
    • The most obvious truth is that beasts are endowed with thought and reason as well as men.
    • The arguments in this case are so obvious, that they never escape the most stupid and ignorant.
  • We are conscious that we are guided by reason and design in adapting means to ends.
    • We do not ignorantly nor casually perform actions for self-preservation, obtaining pleasure, and avoiding pain.
  • When we see other creatures perform like actions and direct them to the ends, all our principles of reason and probability carry us with an invincible force to believe the existence of a like cause.
    • I think it is needless to illustrate this argument by the enumeration of particulars.
      • The smallest attention will be enough.
  • The resemblance between the actions of animals and men is so entire.
    • The very first action of the first animal we examine, will afford us an incontestable argument for the present doctrine.
  • This doctrine:
    • is as useful as it is obvious
    • furnishes us with a kind of touchstone, by which we may try every system in this species of philosophy.
  • It is from the resemblance of the external actions of animals to the actions we perform, that we judge their internal actions likewise to resemble ours.
    • The same principle of reasoning will make us conclude that since our internal actions resemble each other, their causes must also be resembling.
  • Therefore, when any hypothesis is advanced to explain a mental operation common to men and beasts, we must apply the same hypothesis to both.
    • Every true hypothesis will abide this trial.
    • No false hypothesis will ever be able to endure it.
  • Philosophers have used systems to account for the mind’s actions.
    • Their common defect is that they suppose such a subtlety and refinement of thought that exceeds the capacity of animals and even of children and common humans.
      • They are susceptible of the same emotions and affections as persons of the most accomplishd genius and understanding.
  • Such a subtlety is a dear proof of any system’s falsehood, just as simplicity is its proof of truth.
  • Let us:
    • put our system on the nature of the understanding to this decisive trial.
    • see whether it will equally account for the reasonings of beasts and humans.
  • We distinguish between:
    • the actions of animals which:
      • are of a vulgar nature
      • are on a level with their common capacities
    • the more extraordinary instances of sagacity which they sometimes discover for:
      • their own preservation
      • the propagation of their species.
  • The first kind of instance is a dog that:
    • avoids fire and precipices
    • shuns strangers
    • caresses his master.
  • A second kind of instance is a bird that:
    • carefully chooses the place and materials of her nest
    • sits on her eggs for a due time and in suitable season, with all the precaution that a chemist is capable of in the most delicate projection.
  • I assert the former actions to proceed from a reasoning that is not different, nor founded on different principles, from the reasoning in human nature.
  • There must be some impression immediately present to their memory or senses to be the foundation of their judgment.
    • From the tone of his master’s voice, the dog:
      • infers his masters anger
      • foresees his own punishment.
    • From his smell, the dog judges that his game is not far from him.
  • Secondly, the inference the dog draws from the present impression is built on:
    • experience
    • his observation of the conjunction of objects in past instances.
  • As you vary this experience, he varies his reasoning.
  • Make a beating follow on one sign or motion for some time, and afterwards on another.
    • He will successively draw different conclusions, according to his most recent experience.
  • Let any philosopher:
    • make a trial
    • try to explain belief
    • give an account of the principles which create belief, independent of the influence of custom on the imagination
  • Let his hypothesis be equally applicable to beasts and humans.
    • I promise to embrace his opinion after he has done this.
  • But at the same time, I demand that my system be received as entirely satisfactory, if it be the only one which can answer to all these terms.
    • It is obvious that my system is the only one.
  • Beasts never perceive any real connection among objects.
    • Therefore, it is by experience that they infer one from another.
    • They can never by any arguments form a general conclusion, that those objects, of which they have had no experience, resemble those of which they have.
  • It is through custom alone that experience operates on them.
    • All this was obvious with respect to man.
  • But with respect to beasts, there cannot be the least suspicion of mistake.
    • This must be owned to be a strong confirmation, or rather an invincible proof of my system.
  • The force of habit in reconciling us to any phenomenon is best shown in the fact that men:
    • are not astonished at the operations of their own reason, while they admire the instinct of animals
    • find a difficulty in explaining their own reason, merely because it cannot be reduced to the very same principles as instinct.
  • Reason is nothing but a wonderful and unintelligible instinct in our souls.
    • It carries us along a certain train of ideas
    • It endows them with qualities according to their situations and relations.
  • This instinct arises from past observation and experience.
    • But can any one give the ultimate reason why past experience and observation produces such an effect, any more than why nature alone should produce it?
  • Nature may certainly produce whatever can arise from habit.
    • Habit is just one of the principles of nature.
      • Habit derives all its force from nature.

Words: 1835

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