先天功(gong)(gong)(gong),武俠小說中絕學(xue)。《射雕英雄傳》中是「中神(shen)通(tong)」王重陽的(de)絕學(xue)。而其(qi)他書(shu)中解釋為(wei)呼吸吐(tu)納(na)的(de)練功(gong)(gong)(gong)之(zhi)(zhi)法,講究抱元守一,欲練此功(gong)(gong)(gong),身如(ru)處子,不(bu)動如(ru)山,動如(ru)脫(tuo)兔,呼先天下(xia)之(zhi)(zhi)憂而憂,后天下(xia)之(zhi)(zhi)樂而樂。修真活計有何(he)憑,心(xin)死群情(qing)今不(bu)生。精氣充盈功(gong)(gong)(gong)行(xing)具,靈光照耀滿神(shen)京,秘語師傳悟本初,來(lai)時無欠去(qu)無余。神(shen)則守,身則守,此功(gong)(gong)(gong)乃道家獨門(men)不(bu)傳之(zhi)(zhi)秘,以祛百病、調(diao)虛實,治療沉(chen)重內傷。此功(gong)(gong)(gong)極(ji)耗(hao)內力,需(xu)以高深(shen)內功(gong)(gong)(gong)為(wei)輔方(fang)可(ke)學(xue)之(zhi)(zhi),當達于極(ji)限(xian)時,能相觸(chu)無聲,空中暗勁(jing)橫流,風力激(ji)蕩(dang),功(gong)(gong)(gong)法里的(de)奧(ao)秘能使(shi)人潛能意(yi)識(shi)被激(ji)發到極(ji)限(xian),武學(xue)自會步入深(shen)不(bu)可(ke)測之(zhi)(zhi)化境。
在(zai)金庸最(zui)初的(de)小說創(chuang)作中,「先(xian)天(tian)(tian)(tian)功(gong)(gong)」是(shi)「南(nan)帝(di)」段智(zhi)興的(de)絕(jue)學(xue),而「中神通」王重(zhong)陽(yang)的(de)絕(jue)學(xue)卻是(shi)「一(yi)(yi)陽(yang)指(zhi)(zhi)」。后來創(chuang)作《天(tian)(tian)(tian)龍(long)(long)八(ba)(ba)部(bu)》將「一(yi)(yi)陽(yang)指(zhi)(zhi)」改成(cheng)「大理段氏(shi)」武(wu)學(xue)。因此,在(zai)修訂時《射雕英(ying)雄傳》、《神雕俠侶(lv)》、《倚天(tian)(tian)(tian)屠龍(long)(long)記》、《天(tian)(tian)(tian)龍(long)(long)八(ba)(ba)部(bu)》這四部(bu)小說時,為了能夠前後呼應,互(hu)相對照,特(te)意將王重(zhong)陽(yang)與(yu)段智(zhi)興的(de)絕(jue)技交(jiao)換,曾打(da)敗「西(xi)毒(du)(du)」歐陽(yang)鋒(feng)的(de)王重(zhong)陽(yang)傳之以(yi)法,將「先(xian)天(tian)(tian)(tian)功(gong)(gong)」以(yi)「一(yi)(yi)陽(yang)指(zhi)(zhi)」使出,以(yi)剋制「蛤蟆功(gong)(gong)」,以(yi)免(mian)造成(cheng)段智(zhi)興在(zai)第一(yi)(yi)次「華(hua)山論劍」時,身負能夠克制「西(xi)毒(du)(du)」歐陽(yang)鋒(feng)的(de)武(wu)功(gong)(gong)卻只(zhi)是(shi)與(yu)「西(xi)毒(du)(du)」戰成(cheng)平手的(de)古怪(guai)結(jie)果。王重(zhong)陽(yang)徒弟「全真七子(zi)」跟師弟「老頑童(tong)」周(zhou)伯通均未獲得傳授,僅與(yu)「南(nan)帝(di)」段智(zhi)興交(jiao)換過「一(yi)(yi)陽(yang)指(zhi)(zhi)」,用(yong)意是(shi)要(yao)「南(nan)帝(di)」擁有剋制「西(xi)毒(du)(du)」歐陽(yang)鋒(feng)之能。「先(xian)天(tian)(tian)(tian)功(gong)(gong)」配合「一(yi)(yi)陽(yang)指(zhi)(zhi)」除了可(ke)以(yi)完(wan)全對付歐陽(yang)鋒(feng)外,也可(ke)以(yi)祛百病、調虛(xu)實,治療沉重(zhong)內(nei)傷。
在不(bu)同小(xiao)說描述(shu)里有(you)(you)不(bu)同作用(yong),上(shang)官鼎小(xiao)說《沉沙谷》描述(shu):「全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)教(jiao)」和(he)「少(shao)(shao)(shao)林(lin)派(pai)」是最敝帚自珍(zhen),天(tian)下所矚目的就(jiu)是「先天(tian)罡氣(qi)」。全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)與少(shao)(shao)(shao)林(lin)雖然在取勁上(shang)有(you)(you)柔剛之(zhi)別,但(dan)天(tian)下的武(wu)(wu)(wu)學是萬變(bian)不(bu)離其(qi)宗,而以「人(ren)」為原則的。況(kuang)且,兩派(pai)的「先天(tian)氣(qi)功」又是同屬一個范圍的事物。許多「全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)派(pai)」的功訣上(shang)不(bu)夠份量的地方,拿「少(shao)(shao)(shao)林(lin)心(xin)法(fa)」一加對照,便瞭然於胸了,而相(xiang)反的,「少(shao)(shao)(shao)林(lin)心(xin)法(fa)」的缺點也可以用(yong)全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)之(zhi)長來補救。少(shao)(shao)(shao)林(lin)和(he)全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)佛道兩門至高武(wu)(wu)(wu)學水乳交融,少(shao)(shao)(shao)林(lin)和(he)全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)的心(xin)法(fa)一旦合并,舉(ju)世無(wu)敵(di)!使用(yong)者:陸介《長干行》描述(shu):流(liu)落(luo)於關(guan)外「天(tian)池派(pai)」。當年「全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)教(jiao)」仗(zhang)以威(wei)攝武(wu)(wu)(wu)林(lin),幾達(da)百馀年之(zhi)久,後來全(quan)(quan)真(zhen)(zhen)(zhen)(zhen)(zhen)(zhen)沒落(luo),這種武(wu)(wu)(wu)功失(shi)傳,方有(you)(you)少(shao)(shao)(shao)林(lin)武(wu)(wu)(wu)當等派(pai)興起,算(suan)起來,這「先天(tian)功」正(zheng)是武(wu)(wu)(wu)學之(zhi)源(yuan)。當掌力(li)(li)(li)達(da)於極限時(shi),能(neng)相(xiang)觸無(wu)聲(sheng),卻最易傷人(ren)內腑(fu),這種功夫(fu),有(you)(you)個名稱叫做「否(fou)極泰來」,正(zheng)是物極必(bi)反的道理,掌力(li)(li)(li)能(neng)不(bu)聞一些聲(sheng)響,空中暗勁橫流(liu),風力(li)(li)(li)激(ji)蕩(dang)。使用(yong)者:「定天(tian)一戟(ji)」高戰。