Davies, E.B., Pluralism in Mathematics, Philosophical Transactions: Mathematical, Physical and Engineering Sciences, Vol. 363, No. 1835, The Nature of Mathematical Proof (Oct. 15, 2005), pp. 2449-2460

defending pluralism in mathematics, in particular Errett Bishop's constructive approach to mathematics ('Foundations of Constructive Analysis, 1967), more systematic than Brouwer's program of intuitionistic mathematics.
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defending that classical, constructive, computer assisted and various forms of finitistic mathematics can coexist. (..) In different frameworks the answer to a question may be different, but this in no way implies that one or the other is 'right' (anti-Platonistic)
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In classical math the [Exist-sign] refers to Platonic existence, but Bishop used it to refer to the production of an algorith for constructing the relevant quantity (sc stricter conditions for its application).
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Surprisingly Bishop could develop much analysis without using the least upperbound principle or the law of the exlcuded middle.