Abstract The Environmental Attribute Theory (EAT, 环境属性理论) attributes the root of physical motion to the attribute response (属性响应) of objects to the imbalance of the environmental medium field (环境介质场), and force is an a posteriori measure (后验度量) of this response rather than the cause of motion. Based on the EAT framework, this paper systematically discusses two interrelated core propositions: First, the origin of statistical description in physics lies in cognitive informational incompleteness (认知信息不完备), rather than intrinsic randomness (内禀随机性) of nature. Starting from Lin Haibing's Second Law (林海兵第二定律), this paper points out that the necessary and sufficient conditions for determinism of motion are that the initial conditions are knowable and the time evolution of environmental parameters is knowable. Macroscopic objects satisfy these two conditions, so their trajectories are determinate; microscopic particles (electrons, molecules, etc.) have extremely small masses and cannot smooth out high-frequency perturbations of the environmental medium field (density fluctuations, temperature fluctuations, electromagnetic fluctuations, etc.), and the initial conditions and evolution processes of these microscopic fluctuations are in principle not completely knowable, so statistical description must be adopted. The velocity fluctuation variance (速度涨落方差) ⟨∣Δv∣2⟩∝1/m2 reveals dimensionally the suppression mechanism of mass on random effects. Statistical distributions (Maxwell-Boltzmann distribution, 麦克斯韦-玻尔兹曼分布; diffraction patterns, 衍射图样, etc.) are optimal descriptions under conditions of informational incompleteness, rather than fundamental features of natural law. Second, electron diffraction phenomena can be given a deterministic explanation (决定论解释) without introducing wave-particle duality (波粒二象性). This paper proposes the "electron cloud network structure" (电子云网络结构) model: in crystals or solid materials, the extranuclear electron clouds of adjacent atoms couple through the Dianxon medium field (电性子介质场) to form a spatially periodic network structure; incident electrons, subject to Coulomb repulsion, preferentially pass through the grid gaps where the electron cloud density is lower; the statistical cumulative distribution of a large number of electrons is the diffraction pattern, whose mathematical form is equivalent to the squared modulus of the Fourier transform of the permeability function (通透性函数) P(r), naturally yielding the single-slit diffraction formula I(θ)∝(sinβ/β)2, the double-slit interference factor cos2(πdsinθ/λ), and the Bragg condition for crystal diffraction kout−kin=G. This explanation dissolves the paradox of "an electron passing through two slits simultaneously," requires no concept of wave function collapse (波函数坍缩), and restores the deterministic picture of physics. This paper further lists four testable experimental predictions (可检验的实验预言): the dependence of diffraction patterns on the composition of edge materials, the modulation of diffraction patterns by temperature, the reduction of diffraction blurring by environmental shielding, and the repeatability of single-electron landing positions under extreme conditions. These predictions differ fundamentally from the expectations of orthodox quantum mechanics (正统量子力学), forming the basis for decisive experiments (判决性实验). EAT covers the same experimental facts with fewer ontological assumptions (本体论假设) (no wave-particle duality, no collapse, no intrinsic randomness), providing an alternative, deterministic causal explanatory framework (决定论因果解释框架) for understanding quantum phenomena. Keywords: Environmental Attribute Theory (环境属性理论); origin of statistics (统计起源); determinism (决定论); electron diffraction (电子衍射); electron cloud network structure (电子云网络结构); informational incompleteness (信息不完备); wave-particle duality (波粒二象性)