A System of Logic, Ratiocinative and Inductive Quotes

“concise mode of expressing the same meaning is, that inseparable accidents are properties which are universal to the species, but not necessary to it. Thus, blackness is an attribute of a crow,”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Although, however, Hobbes's theory of Predication, according to the well-known remark of Leibnitz, and the avowal of Hobbes himself, 32 renders truth and falsity completely arbitrary, with no standard but the will of men, it must not be concluded that either Hobbes, or any of the other thinkers who have in the main agreed with him, did in fact consider the distinction between truth and error as less real, or attached less importance to it, than other people.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“This leads to the consideration of a third great division of names, into connotative and non-connotative, the latter sometimes, but improperly, called absolute.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Logic, according to the conception here formed of it, has no concern with the nature of the act of judging or believing; the consideration of that act, as a phenomenon of the mind, belongs to another science. Philosophers, however, from Descartes downward, and especially from the era of Leibnitz and Locke, have by no means observed this distinction; and would have treated with great disrespect any attempt to analyze the import of Propositions, unless founded on an analysis of the act of Judgment.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“The following are the classes into which, according to this school of philosophy, Things in general might be reduced: Οὐσία, Substantia. Ποσὸν, Quantitas. Ποιόν, Qualitas. Πρός τι, Relatio. Ποιεῖν, Actio. Πάσχειν, Passio. Ποῦ, Ubi. Πότε, Quando. Κεῖσθακ, Situs. Ἔχειν, Habitus.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Either A is B or C is D,” means, “if A is not B, C is D; and if C is not D, A is B.” All hypothetical propositions, therefore, though disjunctive in form, are conditional in meaning; and the words hypothetical and conditional may be, as indeed they generally are, used synonymously.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“And one of the commonest forms of fallacious reasoning arising from ambiguity, is that of arguing from a metaphorical expression as if it were literal; that is, as if a word, when applied metaphorically, were the same name as when taken in its original sense: which will be seen more particularly in its place.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“An intermediate case is that of a name used analogically or metaphorically; that is, a name which is predicated of two things, not univocally, or exactly in the same signification, but in significations somewhat similar, and which being derived one from the other, one of them may be considered the primary, and the other a secondary signification.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Logic is not the science of Belief, but the science of Proof, or Evidence. In so far as belief professes to be founded on proof, the office of logic is to supply a test for ascertaining whether or not the belief is well grounded. With the claims which any proposition has to belief on the evidence of consciousness—that is, without evidence in the proper sense of the word—logic has nothing to do.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“The sole object of Logic is the guidance of one's own thoughts: the communication of those thoughts to others falls under the consideration of Rhetoric, in the large sense in which that art was conceived by the ancients; or of the still more extensive art of Education.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“To what a degree this loose mode of classing and denominating objects has rendered the vocabulary of mental and moral philosophy unfit for the purposes of accurate thinking, is best known to whoever has most meditated on the present condition of those branches of knowledge.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Truths are known to us in two ways: some are known directly, and of themselves; some through the medium of other truths. The former are the subject of Intuition, or Consciousness; 4 the latter, of Inference.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“is not to be expected that there should be agreement about the definition of any thing, until there is agreement about the thing itself.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“The second general division of names is into concrete and abstract. A concrete name is a name which stands for a thing; an abstract name is a name which stands for an attribute of a thing.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“define logic as the science which treats of the operations of the human understanding in the pursuit of truth.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Geometry is a Deductive Science.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“How to define a name, may not only be an inquiry of considerable difficulty and intricacy, but may involve considerations going deep into the nature of the things which are denoted by the name. Such, for instance, are the inquiries which form the subjects of the most important of Plato's Dialogues; as, “What is rhetoric?” the topic of the Gorgias, or, “What is justice?” that of the Republic. Such, also, is the question scornfully asked by Pilate, “What is truth?” and the fundamental question with speculative moralists in all ages, “What is virtue?”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“The actual existence of the subject of the proposition is therefore only apparently, not really, implied in the predication, if an essential one: we may say, A ghost is a disembodied spirit, without believing in ghosts. But an accidental, or non-essential, affirmation, does imply the real existence of the subject, because in the case of a non-existent subject there is nothing for the proposition to assert.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“When we predicate of any thing an abstract name, we affirm of the thing that it is one or other of these five things; that it is a case of Existence, or of Co-existence, or of Causation, or of Sequence, or of Resemblance.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Besides the propositions which assert Sequence or Co-existence, there are some which assert simple Existence; 36 and others assert Causation, which, subject to the explanations [pg 083] which will follow in the Third Book, must be considered provisionally as a distinct and peculiar kind of assertion.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“When a general name stands for each and every individual which it is a name of, or in other words, which it denotes, it is said by logicians to be distributed, or taken distributively. Thus, in the proposition, All men are mortal, the subject, Man, is distributed, because mortality is affirmed of each and every man.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“An example of this is, when the simple propositions are connected by the particle or; as, either A is B or C is D; or by the particle if; as, A is B if C is D. In the former case, the proposition is called disjunctive, in the latter, conditional: the name hypothetical was originally common to both.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“This, however, only shows that there is an ambiguity in the word is; a word which not only performs the function of the copula in affirmations, but has also a meaning of its own, in virtue of which it may itself be made the predicate of a proposition.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“This, until a better can be suggested, may serve as a substitute for the Categories of Aristotle considered as a classification of Existences. The practical application of it will appear when we commence the inquiry into the Import of Propositions; in other words, when we inquire what it is which the mind actually believes, when it gives what is called its assent to a proposition.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Feelings are of four sorts: Sensations, Thoughts, Emotions, and Volitions. What are called Perceptions are merely a particular case of Belief, and Belief is a kind of thought. Actions are merely volitions followed by an effect.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“when we say of any one that he is generous. The word generosity expresses a certain state of mind, but being a term of praise, it also expresses that this state of mind excites in us another mental state, called approbation.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“This is evidently an incorrect application of the word same ; for the feeling which I had yesterday is gone, never to return; what I have to-day is another feeling, exactly like the former, perhaps, but distinct from it; and it is evident that two different persons can not be experiencing the same feeling, in the sense in which we say that they are both sitting at the same table.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“It may be asked, how come we to ascribe our sensations to any external cause? And is there sufficient ground for so ascribing them? It is known, that there are metaphysicians who have raised a controversy on the point; maintaining that we are not warranted in referring our sensations to a cause such as we understand by the word Body, or to any external cause whatever.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“In consequence of this perversion of the word Being, philosophers looking about for something to supply its place, laid their hands upon the word Entity, a piece of barbarous Latin, invented by the schoolmen to be used as an abstract name, in which class its grammatical form would seem to place it: but being seized by logicians in distress to stop a leak in their terminology, it has ever since been used as a concrete name.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive

“Yet the same gradual decay to which, after a certain age, all the language of psychology seems liable, has been at work even here. If you call virtue an entity, you are indeed somewhat less strongly suspected of believing it to be a substance than if you called it a being; but you are by no means free from the suspicion.”
― John Stuart Mill, A System of Logic: Ratiocinative and Inductive