The higher education sector is now focussed on the task of creating graduates who are able to deal with the novel, complex, unstructured problems they will encounter in the 21st century workforce (Brew, 2010). Within science, the central role of hypothetico-deductive reasoning in ‘thinking like a scientist’ is well established (Dunbar and Fugelsang, 2005), and in bioscience education, understanding ‘testable hypotheses’ has become a threshold concept (Taylor and Meyer, 2010) and a key driver of curriculum transformation (Elliot et al, 2010). From a large database of responses provided by undergraduate biology students to the question “What is a hypothesis?” Taylor et al (2011) developed a 48 item psychometric instrument capturing variation in student understanding of this threshold concept. A version of this instrument has now been trialled with eight hundred undergraduate science students enrolled in a first year, second semester biology course. Exploratory factor analysis of their responses has revealed five factors which vary along dimensions of epistemic maturity and understanding of disciplinary heuristics. These factors are interpreted as representing the initial 'critical features' of the threshold concept as it 'comes into view'. Specifically, students were found to conceptualise hypotheses most simplistically as based on facts, or hold more advanced conceptions about the predictive utility of hypotheses (indicating an awareness of hypothetico-predictive reasoning) and to hypotheses as testable statements (indicating an awareness of hypothetico-deductive reasoning) used in the development of new scientific knowledge. Further, student conceptions varied on the role of observations, experiments and controlling variables in judging the validity of hypotheses. This snapshot characterises the conceptions about hypothesis held by early stage undergraduate science students, providing insights into the ways students are beginning to understand the heuristics used to judge the evidence that builds scientific knowledge in their discipline, as they embark on the journey toward thinking like a scientist.