A method for separating a substrate made of glass, glass ceramic and/or silicon, wherein defects are introduced at a distance from one another into the substrate along a predetermined separation line using at least one pulsed laser beam, the material of the substrate being transparent to the laser pulses; wherein both the average spacing between adjacent defects and the number of laser pulses for producing a respective defect are selected such that a) the breaking stress σ B for separating the substrate along the separation line is smaller than a first reference stress σ R1 which depends on the respective substrate; that b) the edge strength σk of the separation edge obtained after separation is greater than a second reference stress σ R2 which depends on the respective substrate; and that c) the substrate can be separated after the defects have been introduced by applying a stress along the separation line; and wherein the first and the second reference stresses are identical, σ R1 = σ R2 and are specified as a maximum thermal stress σ th which depends on the material of the substrate; or in the case of a chemically or thermally toughened substrate as an internal tensile stress σ CT defined by the properties of the toughened substrate; wherein in the first case, the maximum thermal stress σ th can be determined according to the formula σ th = 0.5·α·E·(T g - 100 °C), wherein α denotes the coefficient of thermal expansion of the material of the substrate, E denotes the Young's modulus of the material of the substrate, and T g denotes the glass transition temperature of the material of the substrate; and wherein in the second case the internal tensile stress σ CT can be determined for a chemically toughened substrate according to the formula σ CT = (σ CS ·d L)/(d - 2d L), or for a thermally toughened substrate according to the formula σ CT = σ CS /2, wherein σ CS is the surface compressive stress of the toughened substrate, d L is the penetration depth of the preliminary stress, and d is the thickness of the substrate; or wherein σ R1 ≤ C R1 ·α·E·(T g - 100 °C) applies for the first reference stress, and σ R2 ≥ C R2 ·α·E·(T g - 100 °C) applies for the second reference stress, wherein C R1 and C R2 are reference stress coefficients with C R1 = 0.5/k and C R2 = 0.5·k and k = 1.5, preferably k = 2, most preferably k = 2.5, and wherein α denotes the coefficient of thermal expansion of the material of the substrate, E denotes the Young's modulus of the material of the substrate, and T g denotes the glass transition temperature of the material of the substrate. wherein defects are introduced at a distance from one another into the substrate along a predetermined separation line using at least one pulsed laser beam, the material of the substrate being transparent to the laser pulses; wherein both the average spacing between adjacent defects and the number of laser pulses for producing a respective defect are selected such that a) the breaking stress σ B for separating the substrate along the separation line is smaller than a first reference stress σ R1 which depends on the respective substrate; that b) the edge strength σk of the separation edge obtained after separation is greater than a second reference stress σ R2 which depends on the respective substrate; and that c) the substrate can be separated after the defects have been introduced by applying a stress along the separation line; and wherein the first and the second reference stresses are identical, σ R1 = σ R2 and are specified as a maximum thermal stress σ th which depends on the material of the substrate; or in the case of a chemically or thermally toughened substrate as an internal tensile stress σ CT defined by the properties of the toughened substrate; wherein in the first case, the maximum thermal stress σ th can be determined according to the formula σ th = 0.5·α·E·(T g - 100 °C), wherein α denotes the coefficient of thermal expansion of the material of the substrate, E denotes the Young's modulus of the material of the substrate, and T g denotes the glass transition temperature of the material of the substrate; and wherein in the second case the internal tensile stress σ CT can be determined for a chemically toughened substrate according to the formula σ CT = (σ CS ·d L)/(d - 2d L), or for a thermally toughened substrate according to the formula σ CT = σ CS /2, wherein σ CS is the surface compressive stress of the toughened substrate, d L is the penetration depth of the preliminary stress, and d is the thickness of the substrate; or wherein σ R1 ≤ C R1 ·α·E·(T g - 100 °C) applies for the first reference stress, and σ R2 ≥ C R2 ·α·E·(T g - 100 °C) applies for the second reference stress, wherein C R1 and C R2 are reference stress coefficients with C R1 = 0.5/k and C R2 = 0.5·k and k = 1.5, preferably k = 2, most preferably k = 2.5, and wherein α denotes the coefficient of thermal expansion of the material of the substrate, E denotes the Young's modulus of the material of the substrate, and T g denotes the glass transition temperature of the material of the substrate.