If Ideas Had Shapes

A quoteblog ranging from philosophers in bathrobes to galaxy-rises

Tag: logic

Douglas Adams – The Salmon of Doubt (2002)

“Listen. In the past, people would stare into the fire for hours when they wanted to think. Or stare into the sea. The endless dancing shapes and patterns would reach far deeper into our minds than we could manage by reason and logic. You see, logic can only proceed from the premises and assumptions we already make, so we just drive round and round in little circles like little clockwork cars. We need dancing shapes to lift us and carry us, but they’re harder to find these days. You can’t stare into a radiator. … All we have to stare into is the white noise. The stuff we sometimes call information, but which is really just a babble rising in the air.”

“But without logic…”

“Logic comes afterwards. It’s how we retrace our steps. It’s being wise after the event. Before the event you have to be very silly.”


Douglas Adams – The Salmon of Doubt (2002)

Dirk stood up and took a deep breath. What the hell was going on? He felt that his whole world was spinning very slowly in what was, as far as he could judge, an anticlockwise direction. That prompted a vague recollection that the last time he had drunk any tequila, it had made his world spin slowly in a clockwise direction. That was obviously what he needed if he was going to be able to think about this clearly.

Douglas Hofstadter – Metamagical Themas (1985)

It always seems refreshing to see how magazines, in their letters columns, willingly publish letters highly critical of them. I say “seems”, because often those letters are printed in pairs, both raking the magazine over the coals but from opposite directions. For example, a right-wing critic and a left-wing critic both chastise the magazine for leaning too far the wrong way. The upshot is of course that the magazine doesn’t even have to say a thing in its own defense, for it is a kind of cliché that if you manage to offend both parties in a disagreement, you certainly must be essentially right! That is, the truth is supposedly always in the middle—a dangerous fallacy.

Terry Pratchett – Unseen Academicals (2009)

…but she was not Her.*

*The Egregious Professor of Grammar and Usage would have corrected this to ‘she was not she’, which would have caused the Professor of Logic to spit out his drink.

George Eliot – “Evangelical Teaching” (1855)

What is for them a state of emotion submerging the intellect is with him a formula imprisoning the intellect, depriving it of its proper function–the free search for truth–and making it the mere servant-of-all-work to a foregone conclusion. Minds fettered by this doctrine no longer inquire concerning a proposition whether it is attested by sufficient evidence, but whether it accords with Scripture; they do not search for facts, as such, but for facts that will bear out their doctrine…. It is easy to see that this mental habit blunts not only the perception of truth, but the sense of truthfulness, and that the man whose faith drives him into fallacies treads close upon the precipice of falsehood.

(quoted in The Portable Atheist)

David Hume – An Enquiry Concerning Human Understanding (1748)

“…no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavours to establish: And even in that case there is a mutual destruction of arguments, and the superior only gives us an assurance suitable to that degree of force, which remains, after deducting the inferior.”

quoted in The Portable Atheist

David Hume – An Enquiry Concerning Human Understanding (1748)

All effects follow not with like certainty from their supposed causes. Some events are found, in all countries and all ages, to have been constantly conjoined together: Others are found to have been more variable, and sometimes to disappoint our expectations; so that, in our reasonings concerning matter of fact, there are all imaginable degrees of assurance, from the highest certainty to the lowest species of moral evidence. A wise man, therefore, proportions his belief to the evidence.

Suppose, for instance, that the fact, which the testimony endeavours to establish, partakes of the extraordinary and the marvellous; in that case, the evidence, resulting from the testimony, admits of a diminution, greater or less, in proportion as the fact is more or less unusual.

quoted in The Portable Atheist

Richard Dawkins – The God Delusion (2006)

However statistically improbable the entity you seek to explain by invoking a designer, the designer himself has got to be at least as improbable.

Richard Dawkins – The God Delusion (2006)

The fact that a question can be phrased in a grammatically correct English sentence doesn’t make it meaningful, or entitle it to our serious attention.

Richard Dawkins – The God Delusion (2006)

The fact that we can neither prove nor disprove the existence of something does not put existence and non-existence on an even footing.