\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows,shapes,chains}


\begin{figure}
    \tikzstyle{startstop} = [rectangle, text centered, draw = black, fill = white]
    \tikzstyle{arrow} = [->,>=stealth]
    \begin{tikzpicture}
        \node(assum)[startstop]  {Assumption};
        \node(fprop)[startstop,below of=assum,yshift=-0.2cm, left of = assum, xshift=-1cm]{Formal Proportion};
        \node(eprop)[startstop,right of = fprop, xshift = 4cm]{Empirical Proposition};
        \node(test)[startstop, blow of = eprop, yshift = -0.2cm]{Test by Data};
        \node(theory)[startstop, blow of = test, yshift = -0.2cm,left of = test, xshift = -1cm]{Wrong Theory};
        \node(assump)[startstop, blow of = test, right of = theory, yshift = -0.2cm, xshift = 4cm ]{Assumptions not met};
        \node(conf)[startstop, right of = test, xshift = 2 cm]{Confident};
        \draw[arrow](assum) -- (fprop);
        \draw[arrow](assum) -- (eprop);
        \draw[arrow](eprop) -- (test);
        \draw[arrow](test) -- \node[above]{Yes}(conf);
        \draw[arrow](test) -- \node[left]{No}(theory);
        \draw[arrow](test) -- \node[right]{No}(assump);
    \end{tikzpicture}
\end{figure}
\end{document}