ðə θˈɜːd mˈɛθəd tˈeɪks θˈiəɹiz ðæt ɑːɹ pɹˈiːviəsli ɛɡzˈɪstɪŋ ænd mˌeɪks ðætðə bˈeɪslaɪn fɹʌm wˈɪtʃ fˈɜːðɚ ɹᵻsˈɜːtʃ kæn bˈɪld əpˌɑːn.
The third method takes theories that are previously existing and makes that the baseline from which further research can build upon.