Sean Carroll, blogger-in-chief at C

Sean Carroll, blogger-in-chief at Cosmic Variance, has ventured abroad from his palatial Californian residence and is currently slumming it in a little town called Oxford where he is attending a small conference in celebration of the 70th birthday of George Ellis. In fact he’s been posting regular live commentaries on the proceedings which I’ve been following with great interest. It looks an interesting and unusual meeting because it involves both physicists and philosophers and it is based around a series of debates on topics of current interest. See Sean’s posts here, here and here for expert summaries of the three days of the meeting.

Today’s dispatches included an account of George’s own talk which appears to have involved delivering a polemic against the multiverse, something he has been known to do from time to time. I posted something on it myself, in fact. I don’t think I’m as fundamentally opposed as Geroge to the idea that we might live in a bit of space-time that may belong to some sort of larger collection in which other bits have different properties, but it does bother me how many physicists talk about the multiverse as if it were an established fact. There certainly isn’t any observational evidence that this is true and the theoretical arguments usually advanced are far from rigorous.The multiverse certainly is a fun thing to think about, I just don’t think it’s really needed.

There is one red herring that regularly floats into arguments about the multiverse, and that concerns testability. Different bits of the multiverse can’t be observed directly by an observer in a particular place, so it is often said that the idea isn’t testable. I don’t think that’s the right way to look at it. If there is a compelling physical theory that can account convincingly for a realised multiverse then that theory really should have other necessary consequences that are testable, otherwise there’s no point. Test the theory in some other way and you test whether the multiverse emanating from it is sound too.

However, that fairly obvious statement isn’t really the point of this piece. As I was reading Sean’s blog post for today you could have knocked me down with a feather when I saw my name crop up:

Orthodoxy is based on the beliefs held by elites. Consider the story of Peter Coles, who tried to claim back in the 1990’s that the matter density was only 30% of the critical density. He was threatened by a cosmological bigwig, who told him he’d be regarded as a crank if he kept it up. On a related note, we have to admit that even scientists base beliefs on philosophical agendas and rationalize after the fact. That’s often what’s going on when scientists invoke “beauty” as a criterion.

George was actually talking about a paper we co-wrote for Nature in which we went through the different arguments that had been used to estimate the average density of matter in the Universe, tried to weigh up which were the more reliable, and came to the conclusion that the answer was in the range 20 to 40 percent of the critical density. There was a considerable theoretical prejudice at the time, especially from adherents of inflation, that the density should be very close to the critical value, so we were running against the crowd to some extent. I remember we got quite a lot of press coverage at the time and I was invited to go on Radio 4 to talk about it, so it was an interesting period for me. Working with George was a tremendous experience too.

I won’t name the “bigwig” George referred to, although I will say it was a theorist; it’s more fun for those working in the field to guess for themselves! Opinions among other astronomers and physicists were divided. One prominent observational cosmologist was furious that we had criticized his work (which had yielded a high value of the density). On the other hand, Martin Rees (now “Lord” but then just plain “Sir”) said that he thought we were pushing at an open door and was surprised at the fuss.

Later on, in 1996, we expanded the article into a book in which we covered the ground more deeply but came to the same conclusion as before. The book and the article it was based on are now both very dated because of the huge advances in observational cosmology over the last decade. However, the intervening years have shown that we were right in our assessment: the standard cosmology has about 30% of the critical density.

Of course there was one major thing we didn’t anticipate which was the discovery in the late 1990s of dark energy which, to be fair, had been suggested by others more prescient than us as early as 1990. You can’t win ‘em all.

So that’s the story of my emergence as a crank, a title to which I’ve tried my utmost to do justice since then. Actually, I would have liked to have had the chance to go to George’s meeting in Oxford, primarily to greet my ertswhile collaborator whom I haven’t seen for ages. But it was invitation-only. I can’t work out whether these days I’m too cranky or not cranky enough to get to go to such things. Looking at the reports of the talks, I rather think it could be the latter.

Now, anyone care to risk the libel laws and guess who Professor BigWig was?

Hasil (Bahasa Indonesia) 1:

Sean Carroll, blogger-in-chief di Cosmic varians, telah berkelana ke luar negeri dari kediamannya California yang megah dan saat ini adalah slumming di kota kecil bernama Oxford dimana ia menghadiri konferensi kecil dalam perayaan ulang tahun ke-70 George Ellis. Bahkan ia telah posting komentar biasa hidup pada proses yang saya sudah mengikuti dengan penuh minat. Terlihat menarik dan tidak biasa pertemuan karena melibatkan baik fisikawan dan filsuf dan didasarkan sekitar serangkaian perdebatan topik terkini. Lihat Sean posting di sini, sini dan di sini untuk ahli ringkasan dari tiga hari pertemuan.Hari ini dispatches termasuk account George's ceramah yang tampaknya telah terlibat memberikan polemik terhadap multiverse, sesuatu yang ia telah dikenal untuk melakukan dari waktu ke waktu. Aku diposting sesuatu itu sendiri, pada kenyataannya. Saya tidak berpikir saya sebagai dasarnya menentang sebagai George pada gagasan bahwa kita hidup dalam sedikit ruang-waktu yang mungkin milik beberapa koleksi semacam besar di mana potongan lain memiliki properti yang berbeda, tetapi itu mengganggu saya fisikawan berapa banyak berbicara tentang multiverse seolah-olah itu adalah sebuah fakta mapan. Tentu saja tidak ada bukti pengamatan bahwa ini benar dan argumen teoritis biasanya maju adalah jauh dari ketat. Multiverse pasti adalah menyenangkan hal untuk berpikir tentang, saya hanya tidak berpikir itu benar-benar diperlukan.There is one red herring that regularly floats into arguments about the multiverse, and that concerns testability. Different bits of the multiverse can’t be observed directly by an observer in a particular place, so it is often said that the idea isn’t testable. I don’t think that’s the right way to look at it. If there is a compelling physical theory that can account convincingly for a realised multiverse then that theory really should have other necessary consequences that are testable, otherwise there’s no point. Test the theory in some other way and you test whether the multiverse emanating from it is sound too.However, that fairly obvious statement isn’t really the point of this piece. As I was reading Sean’s blog post for today you could have knocked me down with a feather when I saw my name crop up: Orthodoxy is based on the beliefs held by elites. Consider the story of Peter Coles, who tried to claim back in the 1990’s that the matter density was only 30% of the critical density. He was threatened by a cosmological bigwig, who told him he’d be regarded as a crank if he kept it up. On a related note, we have to admit that even scientists base beliefs on philosophical agendas and rationalize after the fact. That’s often what’s going on when scientists invoke “beauty” as a criterion.George was actually talking about a paper we co-wrote for Nature in which we went through the different arguments that had been used to estimate the average density of matter in the Universe, tried to weigh up which were the more reliable, and came to the conclusion that the answer was in the range 20 to 40 percent of the critical density. There was a considerable theoretical prejudice at the time, especially from adherents of inflation, that the density should be very close to the critical value, so we were running against the crowd to some extent. I remember we got quite a lot of press coverage at the time and I was invited to go on Radio 4 to talk about it, so it was an interesting period for me. Working with George was a tremendous experience too.I won’t name the “bigwig” George referred to, although I will say it was a theorist; it’s more fun for those working in the field to guess for themselves! Opinions among other astronomers and physicists were divided. One prominent observational cosmologist was furious that we had criticized his work (which had yielded a high value of the density). On the other hand, Martin Rees (now “Lord” but then just plain “Sir”) said that he thought we were pushing at an open door and was surprised at the fuss.Later on, in 1996, we expanded the article into a book in which we covered the ground more deeply but came to the same conclusion as before. The book and the article it was based on are now both very dated because of the huge advances in observational cosmology over the last decade. However, the intervening years have shown that we were right in our assessment: the standard cosmology has about 30% of the critical density.Of course there was one major thing we didn’t anticipate which was the discovery in the late 1990s of dark energy which, to be fair, had been suggested by others more prescient than us as early as 1990. You can’t win ‘em all.So that’s the story of my emergence as a crank, a title to which I’ve tried my utmost to do justice since then. Actually, I would have liked to have had the chance to go to George’s meeting in Oxford, primarily to greet my ertswhile collaborator whom I haven’t seen for ages. But it was invitation-only. I can’t work out whether these days I’m too cranky or not cranky enough to get to go to such things. Looking at the reports of the talks, I rather think it could be the latter.Now, anyone care to risk the libel laws and guess who Professor BigWig was?

Hasil (Bahasa Indonesia) 2:

Sean Carroll, blogger-in-chief di Cosmic Variance, telah berkelana di luar negeri dari kediaman California mewahnya Dan saat slumming di sebuah kota kecil bernama Oxford di mana ia menghadiri konferensi kecil di perayaan ulang tahun ke-70 dari George Ellis. Bahkan dia telah mem-posting komentar hidup biasa pada proses yang saya sudah mengikuti dengan minat yang besar. Kelihatannya pertemuan menarik dan tidak biasa karena melibatkan kedua fisikawan dan filsuf dan didasarkan sekitar serangkaian perdebatan tentang topik yang menarik saat ini. Lihat posting Sean di sini, sini dan di sini untuk ringkasan ahli dari tiga hari pertemuan. Kiriman hari ini termasuk akun pembicaraan George sendiri yang tampaknya telah terlibat memberikan polemik terhadap multiverse, sesuatu yang telah dikenal untuk melakukan dari waktu ke waktu. Aku diposting sesuatu di sendiri, pada kenyataannya. Saya tidak berpikir saya sebagai fundamental bertentangan dengan Geroge untuk gagasan bahwa kita hidup dalam sedikit ruang-waktu yang mungkin milik semacam koleksi yang lebih besar di mana potongan lain memiliki sifat yang berbeda, tapi itu tidak mengganggu saya bagaimana banyak fisikawan berbicara tentang multiverse seolah-olah itu fakta yang mapan. Ada tentu tidak ada bukti pengamatan bahwa ini adalah benar dan argumen teoritis biasanya maju jauh dari rigorous.The multiverse tentu adalah hal yang menyenangkan untuk dipikirkan, saya hanya tidak berpikir itu benar-benar dibutuhkan. Ada satu ikan merah yang teratur mengapung ke argumen tentang multiverse, dan yang menyangkut testability. Bit yang berbeda dari multiverse tidak dapat diamati secara langsung oleh pengamat di tempat tertentu, sehingga sering dikatakan bahwa ide tersebut tidak dapat diuji. Saya tidak berpikir itu cara yang tepat untuk melihat itu. Jika ada teori fisik menarik yang dapat menjelaskan meyakinkan untuk menyadari multiverse kemudian bahwa teori harus benar-benar memiliki konsekuensi lain yang diperlukan yang dapat diuji, jika tidak ada gunanya. Menguji teori dalam beberapa cara lain dan Anda menguji apakah multiverse yang berasal dari itu suara juga. Namun, pernyataan cukup jelas tidak benar-benar titik bagian ini. Ketika saya sedang membaca posting blog Sean untuk hari ini Anda bisa mengetuk saya turun dengan bulu ketika saya melihat tanaman nama saya up: Ortodoks didasarkan pada keyakinan yang dipegang oleh elit. Pertimbangkan kisah Peter Coles, yang mencoba untuk mengklaim kembali pada tahun 1990 bahwa kepadatan materi hanya 30% dari densitas kritis. Dia diancam oleh tokoh kosmologis, yang mengatakan kepadanya dia akan dianggap sebagai engkol jika ia terus itu. Pada catatan terkait, kita harus mengakui bahwa bahkan para ilmuwan keyakinan dasar pada agenda filosofis dan merasionalisasi setelah fakta. Itu sering apa yang terjadi ketika para ilmuwan memanggil "keindahan" sebagai kriteria. George sebenarnya berbicara tentang kertas kami ikut menulis untuk Alam di mana kita pergi melalui argumen yang berbeda yang telah digunakan untuk memperkirakan kepadatan rata-rata materi di alam semesta , mencoba menimbang-nimbang yang lebih handal, dan sampai pada kesimpulan bahwa jawabannya adalah di kisaran 20 sampai 40 persen dari kerapatan kritis. Ada prasangka teoritis yang cukup pada saat itu, terutama dari penganut inflasi, bahwa kepadatan harus sangat dekat dengan nilai kritis, jadi kami berjalan terhadap kerumunan sampai batas tertentu. Aku ingat kita punya cukup banyak liputan pers pada saat itu dan saya diundang untuk pergi pada Radio 4 membicarakannya, jadi itu adalah periode yang menarik bagi saya. . Bekerja dengan George adalah pengalaman yang luar biasa juga saya tidak akan nama "tokoh" George disebut, meskipun saya akan mengatakan itu adalah sebuah teori; itu lebih menyenangkan bagi mereka yang bekerja di lapangan untuk menebak untuk diri mereka sendiri! Pendapat antara para astronom dan fisikawan lainnya dibagi. Satu kosmolog observasional yang menonjol adalah marah bahwa kami telah mengkritik karyanya (yang telah menghasilkan nilai tinggi densitas). Di sisi lain, Martin Rees (sekarang "Tuhan" tapi kemudian sekadar "Sir") mengatakan bahwa dia pikir kami mendorong pintu yang terbuka dan terkejut melihat ribut-ribut. Kemudian, pada tahun 1996, kami memperluas artikel menjadi Buku di mana kita menutupi tanah lebih dalam, tetapi sampai pada kesimpulan yang sama seperti sebelumnya. Buku dan artikel itu didasarkan pada sekarang kedua sangat tanggal karena kemajuan besar dalam kosmologi observasional selama dekade terakhir. Namun, tahun-tahun telah menunjukkan bahwa kami berada tepat di penilaian kami: kosmologi standar memiliki sekitar 30% dari densitas kritis. Tentu saja ada satu hal utama yang kita tidak mengantisipasi yang penemuan di akhir 1990-an energi gelap yang, untuk menjadi adil, telah disarankan oleh orang lain lebih dari kita terus mata sedini 1990. Anda tidak bisa menang mereka semua. Jadi itulah cerita tentang munculnya saya sebagai engkol, judul yang saya sudah mencoba yang terbaik saya untuk melakukan keadilan sejak saat itu. Sebenarnya, saya akan senang memiliki kesempatan untuk pergi ke pertemuan George di Oxford, terutama untuk menyambut kolaborator ertswhile saya yang saya belum melihat untuk usia. Tapi itu undangan-satunya. Saya tidak bisa bekerja tahu apakah hari ini aku terlalu rewel atau tidak cukup rewel untuk bisa pergi ke hal-hal seperti itu. Melihat laporan dari pembicaraan, saya lebih berpikir itu bisa menjadi yang terakhir. Sekarang, ada yang peduli untuk risiko hukum pencemaran nama baik dan tebak siapa Profesor tokoh itu?